ula- primarily denotes joining or connecting one thing with another, especially joining separated ends or adding one part onto another. In Irk Bitig 48 it occurs in the parallel phrase sınukıŋın sapar men, üzükiŋin ulayur men “I repair your broken things; I join your torn things”. The contrast suggests that “repair” is a contextual result of ula-, while its more basic sense is “to join, connect”. Kaşgari likewise records the verb for joining a cord and describes ulağu neŋ as something attached to another thing, such as a patch on a garment.
From the concrete sense “join, attach, add on” developed the closely related senses “extend, prolong, continue” and, in Old Uyghur texts, “transmit, pass on, hand down”. These developments reflect the common notion of establishing or maintaining continuity. Modern Turkmen ula-, for example, still means both to join things end to end and thereby to lengthen them, while Uzbek ula- preserves the senses “join”, “repair by joining”, “graft”, “connect” and “continue”. It is therefore possible, but not demonstrable, that the Proto-Turkic verb already combined the notions of joining and extending.