Calling

google

ref

late Old English ceallian, from Old Norse kalla ‘summon loudly’.

wiktionary

ref

call +‎  -ing

etymonline

ref

calling (n.)

mid-13c., "outcry, shouting," also "a summons or invitation," verbal noun from call (v.). The sense "vocation, profession, trade, occupation" (1550s) traces to I Corinthians vii.20, where it means "position or state in life."