*sekw- (1)
Proto-Indo-European root meaning "to follow."

It forms all or part of: assign; assignation; associate; association; consequence; consequent; consign; design; designate; designation; dissociate; ensue; execute; extrinsic; insignia; intrinsic; obsequious; persecute; persecution; prosecute; pursue; resign; scarlatina; scarlet; seal (n.1) "design stamped on wax;" second (adj.) "next after first;" second (n.) "one-sixtieth of a minute;" sect; secundine; segue; sequacious; sequel; sequence; sequester; sigil; sign; signal; signify; sociable; social; society; socio-; subsequent; sue; suit; suite; suitor; tocsin.

It is the hypothetical source of Sanskrit sacate "accompanies, follows;" Avestan hacaiti, Greek hepesthai "to follow;" Latin sequi "to follow, come after," secundus "second, the following;" Lithuanian seku "to follow;" Old Irish sechim "I follow."