BT Šab 78a(9) :כל מילתא דשכיחא ולא שכיחא אזול רבנן בתר דשכיחא לקולא‏ : (in) any matter which is (both) frequent and infrequent [i.e. it has a frequent and infrequent use], the scholars followed the frequent (one even) for leniency
See the entire entry for šḵīḥ adj. found, present