William Terry

(male) Probably the most successful of all the Old French names of Germanic origin that were introduced to England by the Normans. It is derived from Germanic wil ‘will, desire’ + helm ‘helmet, protection’. The fact that it was borne by the Conqueror himself does not seem to have inhibited its favour with the ‘conquered’ population: in the first century after the Conquest it was the commonest male name of all, and not only among the Normans. In the later Middle Ages it was overtaken by John, but continued to run second to that name until the 20th century, when the picture became more fragmented.

English and Irish: from the common Norman personal name, T(h)erry (Old French Thierri), composed of the unattested Germanic element þeudo- ‘people’, ‘race’ + rīc ‘power’. Theodoric was the name of the Ostrogothic leader (c. 454–526) who invaded Italy in 488 and established his capital at Ravenna in 493. His name was often taken as a derivative of Greek Theodōros (see Theodore). There was an Anglo-Norman family of this name in County Cork.