An offshoot is a term used to describe a headmate or fragment who is a distinctly separate, yet still similar, copy or piece of another headmate.
The two headmates may be similar in source (for sourced headmates), presentation in headspace, role or function, fronting activity, etc... but are different enough in conscious or other methods of distinction to make them two different headmates.
The term is derived from the English word "offshoot", which may be defined as "a side shoot or branch of a plant".
An offshift is a term used to describe a headmate or fragment who is an offset of a headmate and shifts between being separate and the same as the headmate they are offshifted from.
The term is a combination of the words "offset" and "shift", denoting a shift between individual and same.
A shoot is a headmate who is the base of an offset headmate.
It is based off of offsets in gardening, in which the original plant may have a shoot and multiple offsets or offshoots.