1. Short for "(it) was", "(it) did", "(it) will" or anything similar, as long as the use of "tis" would make
no sense if you replaced it with "It is".
2. Short for "It is". People used to say this in the
1800's but now nobody says it in this sense anymore, unless they are old, somehow socially
isolated, or just "different".
1. Yo' momma tis crunk last night.
2. British person #1:
Tis' a merry day for
tea and biscuits, eh chap?
British person #2: Not really fine man, i have to go be on my jolly way.
British person #1:
Alrighty, cheerio!