The same as drowr, applied to a bird; the swift, a kind of swallow -- swallow.
see HEBREW drowr
H1866. deror
II. דְּרוֺר noun femininePsalm 84:4 swallow 84:4 ("" צִמּוֺר), Che (q. v.) makes simile of quiet, peace, security, and supplies ellipsis; in simile, Proverbs 26:2 לָעוּף כַּדְּרוֺר לָנוּד כַּצִמּוֺר (of groundless curse, which does not alight, i.e. is not fulfilled).