narrow down

Verb
  1. Define clearly (synset 200717446)
    "I cannot narrow down the rules for this game"
    is a type of: determine - fix in scope; fix the boundaries of
    subtypes: concretize - make something concrete
    same as: nail down, narrow, peg down, pin down, specify
  2. Become more focused on an area of activity or field of study (synset 200438402)
    "She specializes in Near Eastern history"
    is a type of: alter, change, vary - become different in some particular way, without permanently losing one's or its former characteristics or essence
    subtypes: overspecialise, overspecialize - become overly specialized
    same as: narrow, specialise, specialize

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