mindmap root((短语)) phrase is applicable to any group of words that recurs frequently but is likely to suggest some distinctive quality, such as triteness, pithiness, or pointedness: a poem made up of several trite ~s strung together. idiom applies to a combination of word elements which is peculiar to the language in which is occurs either in its grammatical relationships or in its nonliteral meaning: "to keep house", "to catch cold", and "to strike a bargain" are ~s. expression may be preferred when reference to a way of expressing oneself is accompanied by a qualifying adjective, phrase, or clause: that's an odd ~. locution a somewhat bookish word, may be chosen when reference is to phrases that are idiomatically peculiar to a language, a group, or a person: a pet ~ of the author.