key into

key into (third-person singular simple present keys into, present participle keying into, simple past and past participle keyed into)

1. (transitive) To put (someone) into (a particular state, emotion etc.). [from 19th c.]
2. (intransitive) To cohere with; to accord with, to be in keeping with. [from 20th c.]
   • 2002, Mary Beard, The Parthenon, Profile Books, published 2010, page 144:

     [T]he sheer insistence here on these myths of Greek victory, and the repeated variations on the theme through different legendary cycles, key into the idea of the Parthenon as a monument of Athenian triumph.

3. (transitive) To make (someone) focus or concentrate on (something); to make (someone) understand. [from 20th c.]

   Walter wasn't on the same page as the rest of us at first, but we talked about it and keyed him into it.