Oxford Basic American Dictionary

something that someone has done after trying hard Climbing Mount Everest was his greatest achievement. She felt a great sense of achievement .

ac . id Ф / 'sesid / noun [ count ]

( chemistry ) a liquid substance that burns things or makes

holes in metal

the acid in your stomach

a • cid rain / |®sid 'rein / noun [ noncount ]

( geography ) rain that has chemicals in it from factories, for example. It causes damage to trees, rivers, and buildings.

ac • knowl • edge aw / sk'nalid3 /

( ac . knowl . edg . es , ac . knowl . edg . ing , ac.knowl .edged )

to agree or accept that something is true

He acknowledged that he had made a mistake.

to write to someone who has sent you a letter, etc. to say that you have received it

She never acknowledged my letter.

to show that you have noticed someone He acknowledged me with a wave.

► ac • knowl • edg • ment |AWL ( also ac . knowl . edge . ment ) / sk'nal^msnt / noun [ count, noncount ]

I didn't receive an acknowledgment of my application.

ac • ne / 'rekni / noun [ noncount ]

( health ) a skin problem, common among young people, that causes red spots, especially on the face

a • Corn / ' eikorn / noun [ count ] a small nut with a base like a cup. Acorns grow on large trees (called oak trees ).

a • cous • tic /э ' kustik/ adjective

( physics ) connected with sound or the way people hear sounds

( music ) (of a musical instrument) not electric

an acoustic guitar —Look at the picture at guitar .

ac • quain • tance / э 'kweintns / noun [count]

a person that you know a little but who is not a close friend

ac • quire AWL / э'kwarar / verb ( ac . quires , ac quir . ing , ac . quired ) ( formal )

to get or buy something

He acquired some English from watching American television shows.

a • cre / ' e^r / noun [ count ] a unit for measuring an area of land; 4,840 square yards a farm of 40 acres

ac • ro • bat / ' rekrebret / noun [ count ]

a person who performs difficult acts such as walking on high ropes, especially in a circus (= a show that travels to different towns )

a .CrOSS О / э кгоз / adverb, preposition

from one side to the other side of something We walked across the field.

A smile spread across her face. The river was about fifty feet across.

on the other side of something There is a bank just across the road. across from

on the opposite side of someone or something

He sat across from me at lunch.

The house across the street from us is for sale.

act 1 О / sekt / verb ( acts , act ing , act ed )

to do something, or to behave in a certain way Doctors acted quickly to save the boy's life after the accident.

Stop acting like a child!

to pretend to be someone else in a play, movie, or television program

-SYNONYM perform

act as something to do the job of another person, usually for a short time

He acted as manager while his boss was away.

act 2O / sekt / noun [ count ]

1 a thing that you do

an act of kindness

Which word?

Act, action, or activity?

Act and action can have the same meaning: It was a brave act. ♦ It was a brave action.

Act , but not action , can be followed by of : It was an act of bravery.

We say activity for something that is done regularly: I like outdoor activities such as walking and skiing.

one of the main parts of a play or an opera (= a musical play )

This play has five acts.

a law that a government makes an act of Congress

the Civil Rights Act

behavior that hides your true feelings