gerund
/ˈdʒerənd ˈजे̮रन्ड्/ noun [C] ( grammar ) a noun, ending in '-ing', that has been made from a verb क्रिया से बनने वाला संज्ञा रूप जो ‘-ing’ से अंत होता है
In the sentence ‘His hobby is collecting stamps’, ‘collecting’ is a gerund.