Fortunately, we're all familiar with the metaphor of a "plot hook".
When something is intended to be handled with hooks it is common to provide it with reinforced loops or holes, securely attached, that are easy to engage with a hook, that will resist wear and tear from handling with hooks, and that will not tear off, slip, or apply the strain in a way that causes damage. The nearest we have to a general term for such things is "grommet".
Some types of RPG campaigns involve player characters being brought together by a freak of circumstance and being carried along by a single vast arc plot towards a shared destination. Such campaigns do not require that the characters be frequently manipulated with plot hooks.
Other campaigns involve characters forming a common purpose to seek out some particular type of adventure together, such as delving dungeons to get experience points. Such teams of characters stay together and seek out gilded holes together without motivation from without and go seek out adventures without needed plot hooks to draw them in. Such campaigns do not require that the characters be frequently manipulated with plot hooks.
Some campaigns involve player characters forming a team that is charged with dealing with missions or commissions, in which the adventures in the form of missions or jobs engage the team, and the individual characters are drawn along because it is their job or their duty to play their part in the work of their team. I liken this to having each character firmly tied by his job or duty to a single big iron ring. The plot hook engages the iron ring, and the characters are severally drawn along.
But there is a kind of campaign in which the the adventures, or adventures under the arc plot, will be episodic and varied. The hook for one might be that a princess is kidnapped and the king offers a reward for her rescue, in the next a dying giant might deliver a package containing the statue of a black bird, in the next a player character's cousin might ask for help dealing with the Mob. In such episodic, non-mission-based campaigns it is useful if each character has a couple of large, stout grommets (plot hook, for engaging with).
Grommets can also be very useful to the GM within adventures, as for being engaged by scene hooks or subplot hooks, and generally to guide PCs in setting up scenes. Though not perhaps essential in campaigns of every structure, they are nearly always at least useful. One of the first steps for a character-player who is collaborating with his GM is to design a character with a number of tastefully-chosen but robust and reusable grommets.
Nosiness can be a grommet. Dependent NPCs can be a grommet. Gallantry can be a grommet. A specific ambition can be a grommet. Avarice can be a grommet. A duty can be a grommet. A beloved possession can be a grommet. An intolerance can be a grommet. Support your local gamemaster: build characters with grommets.
It is also helpful (in the absence of a big iron ring) for all the characters to be firmly roped together with ties of some sort, personal connections of affection, duty, kinship and sort forth, so that when character is hooked and drawn in the rest follow naturally. The original /Star Wars RPG/ from West End had a rule that required that every character had to have such a link to at least one other character. It might even have specified that the party had to be united by a system of such ties.
I don't go so far as to insist on anything so formal. But I like to remind players when their are generating characters that I will find large, strong, well-anchored, versatile grommets very useful. Also, that tying the party together with mutual bonds will simplify my task and speed up play in the early part of every adventure, and will help to avoid the problem of finding that your character has no plausible reason to get involved in a particular adventure at all.
Without grommets, GMs can only sink their hooks into the soft, quivering flesh of player characters—and they sometimes need nasty big wickedly-curved hooks with barbs on them to make sure that the hooks don't simply pull out taking a gobbet of flesh and leaving a ragged wound. In the interests of subtlety, and to save your character from repeated impalements and ugly plothook scars, think of grommets at character-design time. Anchor them firmly. Paint them safety orange.