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

David HaLevi Segal

David ha-Levi Segal , also known as the Turei Zahav after the title of his significant halakhic commentary on the Shulchan Aruch, was one of the greatest Polish rabbinical authorities....

adds the word u'mori (ומורי, "and my master"), which would lengthen the permitted window of opportunity.

Practical example

Prior to consuming any food or beverage, a Jew must recite a blessing

Berakhah

In Judaism, a berakhah, bracha, brokhe is a blessing, usually recited at a specific moment during a ceremony or other activity. The function of a berakhah is to acknowledge God as the source of all blessing...

 to express his or her gratitude to God for providing sustenance,(B.Berachot

Berakhot (Talmud)

Berachot is the first tractate of Seder Zeraim, a collection of the Mishnah that primarily deals with laws relating to plants and farming...

35a) and there are different blessings for different types of food.

If for instance, an individual was just about to take a bite from a carrot, for which the blessing ends borei pri ha'adamah (בורא פרי האדמה, "...the creator of fruits of ground") but instead, erroneously concluded the blessing that applies to fruit, borei pri ha'eitz (בורא פרי העץ, "...the creator of fruits of the tree"), correcting the suffix of the blessing to the appropriate conclusion toch k'dei dibur (i.e. within the alloted 3-second window of time), the error would thus be resolved.