Commonly Confused Words

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Word	Definition/use	Example
affect / effect
affect (v)	influence	The number of users affects the response time.
effect (v)	bring about, cause	To effect a change, cut down the number of users.
effect (n)	result	The effect of too many users is slow response time.
all / all of
all	acceptable in all cases except with a personal pronoun	All the settings have defaults.
all of	used only with a personal pronoun	All of them are listed in Appendix A.
already / all ready / all right
already	beforehand	The writer had already started the outline.
all ready	completely ready	The system will be all ready for testing.
all right	satisfactory (adj); certainly (adv)	All right is correct. Alright is not correct.
among / between
among	three or more items considered collectively	It's difficult to choose among the many content management systems.
between	two or more items considered individually	We’re deciding between Houston, Paris, and Tokyo for the conference.
amount / number
amount	used with collective and mass nouns	Equipping a training center costs a large amount of money.
number	used with countable nouns	They bought a large number of computers for the training center.
assure / ensure / insure
assure	set a person’s mind at rest	We assured them that the project was on track.
ensure	make certain	The procedures were tested thoroughly to ensure that they were correct.
insure	protect with insurance	In most states, cars must be insured before they are registered.
because / since
because	show a cause-effect relationship	The project was finished on time because everyone met the schedule deadlines.
since	from then until now	There have been three people in this position since last spring.
can / may / might
can	know how to, be able to	The server can support up to 45 servers.
may	have permission to, be possible to	You may start working on the project now.
might	be possible to (less certain than "may")	We might finish the project on schedule.
comprise / compose / constitute
comprise	contain	A jury comprises 12 people.
compose	create by joining	A jury is composed of 12 people.
constitute	make up, form	Twelve people constitute a jury.
discrete / discreet
discrete	individually distinct, not continuous	Conversion consists of five discrete steps.
discreet	prudent, showing good judgment	Be discreet when you call me at work.
farther / further
farther	physical distance	Don’t place the unit farther than 10 feet from a vent.
further	in addition, to a greater degree	A further problem is the lack of funds.
if / when / whether
if	in the event that	Tell me if the deadline is Friday.
when	at what time (don’t use "if and when")	Let us know when you’ll finish the draft.
whether	with alternatives, used instead of "if"	Ask whether it's due on Friday or Monday.
imply / infer
imply	suggest	He implied that I didn’t understand.
infer	draw a conclusion	From user questions, the staff inferred that the manual was wrong.
its / it’s
its	possessive form of the pronoun "it"	The printer needs to have its toner cartridge replaced.
it’s	contraction meaning "it is"	It’s time to replace the toner cartridge.
lay / lie
lay	put or set down	Never lay the cartridge on its side.
lie	be at rest, assume a horizontal position	Al’s dog lies under his chair at work.
less / fewer
less	used with collective nouns	We need less staff on this project.
fewer	used with countable nouns	We need fewer managers on this project.
pick up / pickup / pick-up
pick up	to gather up; to acquire	Students must show their university ID to pick up packages.
pickup	a stop to collect passengers, goods, or the things collected	Arrangements made for outgoing package pickup.
pick-up	a stop to collect passengers or goods	Although still grammatically correct, the university prefers to refrain from using the hyphenated version.
precede / proceed
precede	come before	The Internet preceded the World Wide Web.
proceed	continue, go on	Proceed to the next lesson.
press / type / click / hit
press	put force on	Press the Reset button to start again.
type	press a character key on a keyboard	Type the letter A.
click	position the mouse pointer; then press and release the mouse button once. Do not use “click on.”	Acceptable for writing instructions, but not as a way to describe a web link; use descriptive text instead. Don’t: Click here for Orientation information Do: You will also need orientation information Do: Click the Cut button. (an instruction)
hit	strike with force	Don’t hit the keys on the calculator.
principal / principle
principal	most important	The principal topics are written.
principle	rule	Follow the principles of good writing.
regardless / irregardless
regardless	correct	The meeting will continue, regardless of the forecast.
irregardless	incorrect	(Do not use.)
take / bring
take	to convey, away from	The train will take you to the city.
bring	to convey, toward	The bus will bring you here.
that / which / who
that	may refer to people or things; introduces an essential phrase	We purchased the software that provided the necessary formats.
which	refers to things; introduces a nonessential phrase (use a comma)	The new software, which will be installed next week, provides the necessary features.
who	refers to people	Charlotte is the writer who won the prize.