Crossword Clue:

the act of marking

AnswerCrossword Clue
FELTTIPWhat's the point of marking things?
EIDHoliday marking the end of Ramadan
FFFMarking for the opening chords of "Tosca"
TETVietnamese holiday marking the arrival of spring
XIIMarking at the top of many faces
NOONMarking at the north end of a sundial
EVENTHORIZONBoundary marking the limits of a black hole
EID... al-Fitr (holiday marking the close of Ramadan)