Obs. Origin, status, and meaning uncertain; occurs in the alliterative phrase thriven and thro, always commendatory or honorific, and apparently meaning something like ‘excellent.’
(It is not impossible that this may originally have been the same word as THRO a.1 2, and that ‘thriven and thro’ became a stock phrase which was vaguely used; cf. ‘a þro knight, þrivand in armys,’ c. 1400 in THRIVING ppl. a. 1, and the other references there given. But there seems also to have been connection in sense with THRO v., as if it had been taken as ‘grown, become great’; cf. the phrases ‘throd and thriven’ [v.r. ‘wele þriuen’] c. 1300 in THRIVEN ppl. a. 1, ‘thryven ant thowen’ [from THEE v.1] a. 1310 ibid. 2.)
a. 1310. in Wright, Lyric P., 26. He is thrustle thryven in [? and] thro that singeth in sale. Ibid., 39. Wel were him that wiste hire thoht, That thryven ant þro.
13[?]. E. E. Allit. P., A. 867. I seghe, says Iohan, þe loumbe hym stande, On þe mount of syon ful þryuen & þro.
a. 1450. Le Morte Arth., 589. There is no lady of flesshe ne bone In this world so thryve or thro, Thoughe hyr herte were stele or stone, That might hyr loue hald hym fro.
