Toch k'dei dibur

The Hebrew phrase tokh k'dei dibur (תוך כדי דיבור, "within [time] sufficient for speech") is a principle in Jewish law that governs the immediacy with which one must speak words for them to be considered a continuation of what has been stated just prior.

The period of toch k'dei dibur is equivalent to the time necessary to say the words Shalom alecha rebbi (שלום עליך רבי, "Peace unto you, my teacher"), which is somewhat less than three seconds. Mishnah Brurah 206:12, although the Taz adds the word u'mori (ומורי, "and my master"), which would lengthen the permitted window of opportunity.