Which is a formal description of a phrase such as "bits and bobs"?

Question

Which is the name for a festival of Scottish Gaelic song, arts and culture which largely takes the form of formal competitions in choral events, traditional music and spoken word?

Answer 1

Binomial freeze
The description applies to a pair or group of words belonging to the same part of speech, with some semantic relationship, and used together in fixed order as an idiomatic expression or collocation. The words are usually connected by the words "and" or "or". Alternative descriptions are: irreversible binomial, (frozen) binomial, binomial pair, binomial expression, or nonreversible word pair.