Definition of check/call
A check/call is the fact of checking with the intention of call if a player puts in position on us. A check/call is the fact of telling oneself that one check/call is the fact of thinking 1 move in advance. You can check/call for several reasons. One of the reasons for check/call is when you have a draw. You can also check/call when your opponent is standing on top of you and likes to bluff. In short, you can check/call for a very large number of reasons.
2 examples of check/call
The check/call is always out of position. For this reason, both examples will be out of position. In situation number 1, we have 8-9 in the heart out of 9-9-8. Here, betting could cause our opponent to fold. With such a strong hand, we want to keep him in the hand. Check-raiser would show too much strength and again, our opponent could fold. The most logical option is check/call. We check in our turn with the obvious goal of making a call against a bet.
For example number two, you have 8-9 in hearts still, but on A-2-5 with two hearts. In this situation, out of position, if we bet and are raised, we're in a bad situation. The fact of check/call seems more appropriate.