ヤク, つづ.まる, つづ.める, つづま.やか

promise, approximately, shrink

JLPT3 G4 S9 F94

As per # (rise and become evident) + thread → *tie* a knot in a cord (as a sign of a pledge) → *promise*; *conspicuous mark* → *brief*; *summary* (← reduce in making compact; compare 要) → *approximately* (← summary approximating a full report in providing only the gist).

[Full Kanji Etymology List]