tho

Etymology 1

From Middle English tho, tha, from Old English þā (“the, those”, plural), from Proto-West Germanic *þai, from Proto-Germanic *þai (“those”), from Proto-Indo-European *to-, *só (“that”). Cognate with Saterland Frisian do (“the”, plural).

pron

1. (obsolete) Those; they.

Etymology 2

From Middle English tho, tha, from Old English þā (“then, when”), from Proto-Germanic *þa- (“that”), from Proto-Indo-European *to-, *só (“that”). See also German da (“then, thereupon”).

adv

1. (now dialectal) Then; thereupon.
   1481, William Caxton, The History Reynard the Foxː Tho went I near and found Master Reynard, that had left that he first read and sang, and began to play his old play.
   1642, Henry More, Song Soulː Tho I gan closely on his person look.

conj

1. (dialectal) When.

Etymology 3

Mostly found in American English; alteration of though. Compare tho'.

adv

1. (chiefly US) Informal spelling of though.
   I wonder now when I will find time to read it but it is a treasure anyway tho heavy in my knapsack, […] 2009, John Hough, Seen the Glory: A Novel of the Battle of Gettysburg, Simon and Schuster, page 121