The second person singular, indicative mode, present tense, of the substantive verb Be; but formed after the analogy of the plural are, with the ending -t, as in thou shalt, wilt, orig. an ending of the second person sing. pret. Cf. Be. Now used only in solemn or poetical style.
ART
Meaning of ART in English
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012