Definitions of terms (vocabulary) – Technical English Units


Numbers: How to write them (lesson and practice)

  • Although usage varies, most people spell out numbers that can be expressed in one or two words and use figures for other numbers:
  • over two pounds
  • six million dollars
  • after thirty-one years
  • eighty-three people
  • after 126 days
  • only $31.50
  • 6,381 bushels
  • 4.78 litres  

Days and Years

  • December 12, 1965 or 12 December 1965
  • A.D. 1066
  • in 1900
  • in 1971-72 or in 1971-1972
  • the eighties, the twentieth century
  • the 1980’s or the 1980s

Time of Day

  • 8:00 A.M. (or) a.m. (or) eight o’clock in the morning
  • 4:30 P.M. (or) p.m. (or) half-past four in the afternoon


  • 16 Tenth Street
  • 350 West 114 Street

Identification Numbers

  • Room 8
  • Channel 18
  • Interstate 65
  • Henry VIII

Page and Division of Books and Plays

  • page 30
  • chapter 6
  • in act 3, scene 2 (or) in Act III, Scene ii

Decimals and Percentages

  • a 2.7 average
  • 13 1/4 per cent
  • .037 metric ton

Large Round Numbers

  • four billion dollars (or) $4 billion
  • 16,500,000 (or) 16.5 million

Notes on Usage

Repeat numbers in legal or commercial writing.

  • The bill will not exceed one hundred (100) dollars.

Numbers in series and statistics should be consistent.

  • two apples, six oranges, and three bananas
  • NOT: two apples, 6 oranges, and 3 bananas
  • 115 feet by 90 feet (or) 115′ x 90′
  • scores of 25-6 (or) scores of 25 to 6
  • The vote was 9 in favour and 5 opposed

Write out numbers beginning sentences.

  • Six per cent of the group failed.
  • NOT: 6% of the group failed.

Use a combination of figures and words for numbers when such a combination will keep your writing clear.

  • Unclear: The club celebrated the birthdays of 6 90-year-olds who were born in the city. (may cause the reader to read ‘690’ as one number.)
  • Clearer: The club celebrated the birthdays of six 90-year-olds who were born in the city.

Numbers that represent time, dates, ages, sizes, scores, money, and points on a scale

  • in about 6 years
  • 2 days ago
  • at 12 noon
  • $5
  • 6-year-old children

Numbers that represent a place in a series

  • year 7 of an 8-year project
  • room 9
  • Figure 2 (in an article)
  • Chapter 5
  • row 1

Numbers in a list of four or more numbers

  • 1, 2, 4, and 8 bits, respectively

Numbers less than 10 that do not represent exact measurements.

  • only three times
  • four 32-bit words
  • eight lists
  • nine pages
  • a three-way interaction

Any number that begins a sentence, title, or heading.

  • Sixteen-bit processors were used.
  • Thirteen of 20 processors failed.

Common fractions

  • one-fifth of the users
  • execution time was reduced by two thirds
  • in one half the time

Widely accepted phrases

  • the Fourth of July
  • the Ten Commandments

Combined figures and words.

  • 3 million cycles
  • 32 million bytes
  • in 2 three-part modules
  • twenty-four 8-bit words

Ordinal numbers.

Treat ordinal numbers as cardinal numbers

  • a second-order relationship
  • a third-generation chip
  • the 3rd and 12th rows of the matrix

Exercise 1: Each sentence contains at least one error. Correct them.

  1. I bought 3 computers.
  2. I bought three computers and 20 printers.
  3. 10 people came to the meeting at 10 o’clock.
  4. They have sold four million copies of this software so far.
  5. The 1st new computer system is ordered already.
  6. I’ve tried this 2 or 3 times.
  7. This sentence is 6 words long.
  8. This increases processing speed by five per cent.
  9. The screen is 32.56 cm wide and eight cm tall.
  10. Look in lab number seven.
  11. Chapter 7 of this book begins on page 1,230.
  12. The probability of getting this relationship by chance is less than 0.05.
  13. 2 or three weeks ago that bug was fixed.
  14. They voted by a 2/3 majority.
  15. When the result is multiplied by one hundred, you get a percentage.
  16. The first and tenth lines of the matrix contain 0s
  17. Two two-part modules were added.
  18. All of these 8’s have to be written as words.
  19. Please wait outside Room Seven.
  20. This chip has a drawing speed of eight ns/pixel with 32 bits per pixel.

Technical English, practice 1

  1. Circle the correct option:
  • Two different crash test dummies (1) USE/ARE USED in standard European vehicle crash test. The first dummy (2) USE/IS USED for font impact crashes, and the second one is a side-impact crash dummy. The dummies, which (3) MAKE/ARE MADE of steel, aluminium and rubber, (4) CONTAIN/ARE CONTAINED many sensors. Three types of sensing equipment (4) USE/ARE USED: acceleration sensors, lead sensors and motion sensors. The dummy head (5) CONTAINS/ IS CONTAINED three accelerometers which (6) SET/ARE SET at right angles. In addition, a front-impact crash test dummy (6) HAS/ HAVE steel ribs fitted with motion sensors which (7) RECORD/ARE RECORDED front rib movement.

2. Fill in using the given words. One word is EXTRA so you do not need to use it.

wheel-gun, ignition, frame, installed, cloth, unscrew, load, derrickman, pressure
  1. You must loosen the nuts with the _____________________.
  2. Please, check the air ________________ in the tyres.
  3. Always use a clean _________________ to clean the visor.
  4. Thin metal sheets are welded together to a __________________.
  5. The electrical wiring must be carefully _______________.
  6. To check the amount of liquid, __________________ the cap on the reservoir first.
  7. The process of starting the combustion of fuel in the cylinders of an internal combustion engine is called _________________.
  8. A ____________ is a technician who works in the drill crew.
  • Fill in using the given words:
broke, crushed, spill, torn, installed
  1. Be careful not to ____________the coffee on the table.
  2. A van drove into the back of my car and the bumper got _____________.
  3. The documents with the instructions were __________ so he had to print a new one.
  4. They ____________ the handle of my suitcase at the airport.
  5. They ___________ over half the cables in the train tunnel last month.
  • Write the opposite:
  1. put together _________________
  2. raise __________________
  3. audio _________________
  4. old ___________________
  5. recharge ______________
  6. screw _________________
  • Make questions for the given answers:
  1. Ben got a shock because he touched an earthed live wire.
  2. Metal is heated to make it softer.
  3. The first mass-produced pencils were made in Germany about 2200 years ago.
  4. The smoke detectors are installed in most buildings to warn people of wire.
  5. I am writing an email to customer service.
  6. Reading comprehension. Read the text and answer the true or false questions below.

What is GPS?

GPS stands for the Global Positioning System. It can tell you precise location anywhere on the Earth to within 6 metres. A group of 24 or more satellites orbit the Earth at an altitude of 11,000 miles. Every 12 hours, a satellite makes an orbit or one complete cycle in space around the Earth. The satellites transmit signals to receivers on the ground. The user has a GPS receiver which detects the signals from the satellites and calculates their distance from the receiver. Receivers can be held in your hand or mounted in a vehicle, such as a car or a ship. A hand-held receiver is about the size of a mobile phone, but the newer models are even smaller.

  1. GPS is a device which gives information about places on the Earth. _______________
  2. A satellite needs a half a day to make an orbit. _______________
  3. Signals are transmitted from the receivers to satellites. __________________
  4. Receivers are made in many sizes. ________________
  5. Receivers can only be used in cars or other vehicles. ___________________

Fill in the gaps using ONE word only to complete the definitions:

a) When you tighten a screw, it ___________________ clockwise.

b)The antenna on a mobile phone ____________ radio signals.

c) This musical website allows you to ____________________ music.

d) An ammeter is a device which measures electric _________________.


The Internet (vocabulary practice)

  1. Fill in the gaps with the words given in brackets:
Windows, Anti-virus software, Backup, Resolution, Icon, Floppy Disc, Folder, RAM/ROM
  • 1.________ A program that finds and removes viruses from a computer.
  • 2.________ A copy on floppy disk or tape of files on a PC’s hard disk. A backup is used in case the hard disk file(s) are erased or damaged.
  • 3.________ A cheap, removable disk used for storing or transferring information. It is floppy (soft) because it is plastic.
  • 4._________ A sub-division of a computer’s hard disk into which you put files.
  • 5._________ A small image or picture on a computer screen that is a symbol for folders, disks, peripherals, programs etc.
  • 6._________Two types of memory. RAM (Random Access Memory) is the main memory used while the PC is working. RAM is temporary. ROM (Read Only Memory) is for information needed by the PC and cannot be changed.
  • 7._________The number of dots or pixels per inch (sometimes per centimetre) used to create the screen image.
  • 8._________An operating system used by the majority of PCs.

2) Collocations

Verbs + Equipment/ Invention

  1. buy _______________
  2. devise _____________
  3. upgarde ___________
  4. install _____________
  5. originate ___________
  6. buy _______________
  7. patent _____________
  8. operate ____________

3) Save, Find or Go?

  1. ________ time
  2. ________ a partner
  3. ________ mad
  4. ________ the answer
  5. ________ a solution
  6. ________ someone’s life
  7. ________ a replacement
  8. ________ a file