Tide over is a transitive verb (meaning that it is an action that has a direct object). The verb means to aide or provide resources for a short amount of time. It may refer to life-sustaining needs, such as, money or food or sleep, etc. Or, it may be used concerning addictions or simply cravings.
The verb dates back to the early 1800s.
Tide can also be a verb on its own, either transitive or intransitive. Without an object (intransitive) it means to move as the tide moves, in and out or up and down, rhythmic. With an object (transitive) tide means to float or move as if by the tide.