to get hold of someone or something so it cannot get away: to grip, seize, or catch
This verb names the plain physical act of closing a hand around something and keeping it there. What that looks like depends entirely on what is being taken hold of, and the New Testament stretches it across three very different scenes: a hand reached down to a crippled beggar, a squad of temple guards sent after a teacher, and a night of empty fishing nets.
Nine of its twelve appearances describe taking a person captive, and six of those belong to a single running thread in John's Gospel. Again and again people try to seize Jesus and fail, because, as John twice explains, his hour had not yet come. The word quietly becomes a way of tracking who is actually in control of events. In Revelation the same verb returns in the passive for the capture of the beast, and there the seizing finally succeeds.
The other three uses pull in gentler and more ordinary directions. Peter grips the lame man by the right hand and lifts him to his feet, and the disciples spend a whole night on the lake and take nothing. Greek has more specialized verbs for taking and holding. One of them, κρατέω, meaning "to hold fast", stresses keeping a firm grip and having power over what is held; another, ἐπιλαμβάνω, meaning "to take hold of", is often used of reaching out to steady or rescue someone. The verb in view here stays fixed on the moment of the catch itself.