Reinstated from inactive list

Your thread title, "inactive list" is different from "DL." Which one do you mean.

DL is somewhat self-explanatory.

"Inactive list" includes things like death in the family, personal stuff, etc...

When you go onto Baseball America's site and look at "minor league transactions" you see both - Reinstated from DL and Reinstated from inactive list.

What does Reinstated from Inactive List mean exactly?

Inactive, as justbaseball explains, can mean many things, the word meant he was "inactive" for a period of time, then placed back on a roster. A player on son's team left for a few days to go to a wedding (pre planned) so his desigation was "inactive". Sometimes when there is no room yet on a roster, the player may become "inactive" for a day. It usually has no negative implications. Though they can make a player inactive before they are suspended, when deciding what course of action to take.
When a player goes on the DL (even that good old phantom DL) as they move players around, it must be for at least 7 days. So sometimes "inactive" works better for quick reinstatement.

In other words, you can never have more than 25 on an active roster for a team, many times it's just manipulating the roster to move players around, but usually in the case of "inactive" it is used for personal leave of absence.

We had a couple of friends who were starting pitchers, they happen to be on the same team and the club was constantly being put on and taken off the inactive list in between starts late in the season.

I asked one of the scouts who drafted one of the players and he said, like TPM stated, it was a way to expand the line up.