https://en.wikipedia.org/wiki/Thou_shalt_not_kill
Certainly whether or not abortion qualifies as killing is a matter of interpretation, but judging from signs I've driven by I'd say it's not an unpopular interpretation
No matter how popular the interpretation may be, the Bible *DOES NOT* prescribe a viewpoint on whether abortion is killing. Quite the opposite in fact. What little is said relating to it in the Bible is evidence that abortion is something *LESS* than killing.
It is perfectly valid to believe that abortion is murder. But arguments that the Bible says so are based on invalid logic.
There are even verses in the New Testament that some interpret as giving permission to use violence in self defense, an interpretation I reject: Matthew 10:34 and Luke 22:36
So no, the Bible is not especially clear on killing, either.