Combining Character Sequence (Unicode)
Last updated at 12:23 am UTC on 11 December 2015
(Unicode glossary)
A maximal character sequence consisting of either a base character followed by a sequence of one or more characters where each is a combining character, zero width joiner, or zero width non-joiner; or a sequence of one or more characters where each is a combining character, zero width joiner, or zero width non-joiner.
http://www.unicode.org/glossary/#combining_character_sequence
