Respawning occurs after one has voluntarily deconstructed, or died and "released" their corpse. A player will then reappear in a Respawn tube or AMS cloak bubble, wearing a Standard Exo-Suit and minimal weapons and ammo.
A Respawn timer governs how quickly a player transitions from death to respawning. The timer increases with each death, but can be reduced by staying alive longer or with the Bio Laboratory or Speed Module benefits.
Respawning is sometimes refered to simply as Spawning.
A player typically has 4 spawn points: the closest friendly-controlled base, tower, and AMS, if they exist, in addition to the Sanctuary, which is always available. If the player has bound to an AMS and/or base, or has an active Squad Home Base, he/she may respawn there as well even if they are not the closest base/AMS. In the Caverns, the closest Module Building and Redoubt Building are available to spawn from, if your empire controls them.