To concentrate on a particular location; to localize
To focus, or to adjust a focus
To sharpen an image by focusing
To fill a place as a swarm.
To climb by gripping with arms and legs alternately.
To overwhelm as by an opposing army.
To breed multitudes.
To move as a swarm.
To teem, or be overrun with insects, people, etc.
A mass of people, animals or things in motion or turmoil.
A large number of insects, especially when in motion or (for bees) migrating to a new colony.
A group of nodes sharing the same torrent in a BitTorrent network.