ˈ ̷ ̷ ̷ ̷ at iso- +ˌkrōn noun
( -s )
Etymology: International Scientific Vocabulary is- + -chrone (from Greek chronos time)
: a line on a map or chart connecting points at which an event occurs simultaneously or which represent the same time or time difference (as a line showing the distances that may be reached from a central point in a city in the same length of time)