Where does “tráthchlár” come from?

tráthchlár (Irish) comes from Irish tráth, from Old Irish tráth, from Proto-Celtic trātu, from Proto-Indo-European terh₂- — to cross over, pass through, overcome.

tráthchlár (Irish): timetable

Definitions

timetable

Ancestry of “tráthchlár”, step by step

Step	Language	Word	Meaning
1	Irish	tráth	hour; time; day, period
2	Old Irish	tráth	period of time, hour, point in time; day;...
3	Proto-Celtic	trātu	time, hour
4	Proto-Indo-European	terh₂-	to cross over, pass through, overcome

Every word from Proto-Indo-European terh₂- →Every word from Proto-Celtic trātu →Every word from Old Irish tráth →