Lejeune (below) 93, 122, says this headword is a perfect of mei/romai, third person singular, from *se-smor- with Aeolic treatment of intervocalic -sm- and initial psilosis (contrast the Ionic dialect treatment in ei(/marto). But others have regarded it as an aorist.
Entry from the scholia on Homer, Iliad 1.278, where it occurs (web address 1); likewise or similarly in Hesychius and other lexica.
See also mu 859, mu 860, and alpha 1630.