As Solas brings the torch over, Strange frowns, peering at the rune. It certainly is a rune. And his elvish is weak to begin with (nearly nonexistent would be a more accurate descriptor) but Strange knows enough to take a stab at the rune's meaning. And, after a bit of frowning and hemming and hawing, that's what he does.

"Well, it involves fire somehow."

He's kind of right. The rune's more along the lines of a literal conflagration than just 'fire.' But hey, Strange got part of it correct.