What's that you say? Why does Widowmaker have a tattoo meaning "nightmare" in French? I'm glad you asked.
Credit to The Overcast for pointing this out
Widowmaker's tattoo wraps around her forearm, but is supposed to be read as
"araignée du soir, cauchemar"
which translates to
"evening spider, nightmare."
This is a play on the second half of a common french superstition:
"araignée du matin, chagrin, araignée du soir, espoir"
which translates to
"morning spider, grief, evening spider, hope."
Basically, french people think if one of the first things you do in your day is see a spider, your days not gonna get any better, but one at the end of your day means tomorrow you'll be lucky or receive a gift.
Widowmaker's tattoo is a play on this phrase, saying,
"If you see this spider at night, you're getting a nightmare in the shape of a bullet between your eyes"
but I guess that wasn't as elegant. Either way, this is a reference French players will get more out of than Americans.
Via Reddit.