two/ten a penny (British English) (North American English a dime a dozen) ​very common and therefore not valuable. Teachers of history are ten a penny.

two or three at a time; in small numbers People arrived in twos and threes. in two shakes/in a couple of shakes (informal).

two, adj., n., & adv. meanings, etymology, pronunciation and more in the Oxford English Dictionary.

​an expression used especially by children or when speaking to children to talk about passing solid waste from the body. Mum, I need a number two.

There are two meanings listed in OED's entry for the noun two-two. See 'Meaning & use' for definitions, usage, and quotation evidence.

Definition of 2% noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

two-way adjective [usually before noun] moving in two different directions; allowing something to move in two different directions.

Definition of two-four noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and ...

both determiner, pronoun /bəʊθ/ /bəʊθ/ used with plural nouns to mean 'the two' or 'the one as well as the other'

two-way · ​moving in two different directions; allowing something to move in two different directions. two-way traffic; two-way trade · ​(of communication ...