The headword (which must be quoted from somewhere) is present indicative middle, first person plural, of the verb dierei/dw, "I prop up"; see LSJ at web address 1. Same or similar glossing in other lexica, and for something closely comparable see the scholia to Euripides, Hecuba 66, and Hesychius, delta1635 (diereidome/na glossed with sthrizome/nh).