What is a "win in last at-bat"?

Question

On a baseball broadcast tonight, the team statistic "wins in last at-bat" came up. What's the definition of this term?

The announcer was careful to point out that such a win "doesn't have to be a walk-off", and gave as an example San Francisco at Milwaukee, June 8, 2017. This was an extra-innings game in which the visiting Giants scored four runs in the top of the 10th, then held the Brewers scoreless in the bottom of the 10th to win. But the Giants' last at-bat in the top of the 10th didn't score a run at all (it was a ground ball into a double play) so it's not clear to me in what sense they won on their last at-bat.

If it helps, there was a graphic showing the National League leaders for most wins in last at-bat in the 2017 season up to June 9:

Giants            9
Phillies          9
Diamondbacks      7
Braves            7

I tried searching and found a few mentions of games won on the last at-bat, but couldn't find a precise definition.

Answer 1

I don't hear it much outside this specific context, but would generally assume that an at-bat for a team (instead of an individual) covers the portion of a single inning that a team is on offense.

This ESPN story confirms that usage for this statistic.

The definition of a last at-bat win is when the winning run is scored by a team in their final inning at the plate

Answer 2

It means your team took the lead during their last turn at bat.

Let's say a home team took the lead in the 1st at bat of the bottom of the 8th inning, then committed 3 outs, and the visiting team failed to score in the top of the 9th.

It would be a last at bat win for the home team.