† ˈblood-ˌironObs. [f. blood n. + iron n.] An instrument for letting blood; a lancet. c1440Promp. Parv. 40 Bloodeyryn, bledynge yryn.1451Invent. in Test. Ebor. III. 118 De blode yrens et launcettes in j case.1523Fitzherb.Husb. §58 Take a bloud yren..and smyte hym bloudde on bothe sydes.