A Friday that is going so bad, it's more like a Monday. Usually a Tiger Friday is followed by a need to meet friends and socialize to off-set the crappy day.
Fridays are either like lambs or they're like tigers and mawl the TG right out of TGIF. This is a Tiger Friday.
A non-romantic relationship between family members. A distinction in relationships so that people don't jump to the incest conclusion.
Jack and Jill get along very well, they have such a great familationship!