糸いと口ぐち

noun

beginning; start; first step

Refers to the initial stage or the very beginning of something, often implying a small opening that leads to a larger development. Common in phrases like 糸口を見つける (find a starting point) or 糸口をつかむ (get a foothold).

• 問もん題だい解かい決けつの糸いと口ぐちが見みつからない。

  I can't find a starting point for solving the problem.

• 彼かれの一ひと言ことが事じ件けん解かい決けつの糸いと口ぐちとなった。

  His single remark became the first step toward solving the case.

noun

clue; lead; hint

Used when a small piece of information or a trace provides a way into understanding or solving something. Often overlaps with sense 1, but emphasizes the clue-like nature.

• 警けい察さつはまだ有ゆう力りょくな糸いと口ぐちをつかんでいない。

  The police haven't yet found a solid lead.

• そのメモが謎なぞを解とく糸いと口ぐちになった。

  The memo became a clue to solving the mystery.

noun

thread end

Literal meaning: the end of a thread. This is the original, concrete sense, but it is rarely used in modern everyday conversation. Mostly encountered in explanations of the word's origin or in literary contexts.

• 「糸いと口ぐち」の文も字じ通どおりの意い味みは、糸いとの端はしのことだ。

  The literal meaning of 糸口 is the end of a thread.