The meaning of Sol

Hollow World - Michael J Sullivan

"Oh I do like you, Mr. Rogers."   
"I like you too, Sol.  Sol…"  He repeated the name thoughtfully. 
"It's another word for sun," she said.
"And a Martian day," he added. 
"And an abbreviation for solution." 
"And an acronym for shit outta luck". This made Sol laugh. "I never heard that one. It's nice to talk to someone more my age."