Each, apiece, severally, individually, respectively are comparable when they refer to every one of the many or several persons or things comprising a group. All imply distribution.
Each and apiece usually connote equality in the amount or value of what is distributed unless the context indicates otherwise.
Severally stresses the apartness of each of the persons and things involved but at the same time often, especially in legal use, implies that each of them is favored, bound, guilty, or responsible in the same degree as the group as a whole; thus, to try a group of conspirators severally is to try them not jointly, or together, but one at a time and usually on the identical charge; to be bound jointly and severally is to be under obligation as a group and singly as individuals, damages being recoverable from all or from any member of the group.
Individually, like severally, implies a distinction between each member of the group, but it goes further in not suggesting equality (as in responsibility, favor, or disfavor); thus, to try a group of conspirators individually is to try each one on a specific charge, usually on the assumption that they are not equally guilty; to greet each member of a visiting delegation individually is to greet him separately and personally.
Respectively is used only when the persons or things involved in the distribution follow a given order and what is distributed goes to each in the same order.