focal
From Longman Dictionary of Contemporary Englishfocalfo‧cal /ˈfəʊkəl $ ˈfoʊ-/ adjective [only before noun] MAINthe focal thing is the one that people pay most attention to → focus This issue has now become the focal centre of interest.Examples from the Corpusfocal• The initial focal symptoms may be very brief, or they may last longer than 30 minutes.