Other forms: hollows, hollowed, hollowing
Hollow means empty inside. A drum, a chocolate Easter rabbit, an old tree you can put your whole arm into — solid-looking from the outside, nothing in the middle.
Tap something hollow and you get that deep echoing sound, which is why a voice or a cough can be hollow too, and why hollow cheeks and hollow eyes are the sunken ones of somebody ill or worn out. The figurative use does the real work: a hollow promise, a hollow apology, a hollow victory that cost more than it was worth — words with nothing behind them. To hollow something out is to dig the middle out of it. As a noun, a hollow is a small dip in the ground or in the palm of your hand, and ring hollow is the fixed phrase: his thanks rang hollow.
1adjectivehollowHaving an empty space inside.
“The statue looked solid but was hollow all the way up.”
synonyms: empty
2adjectivesound(of a sound) Deep and echoing, as if made in an empty space.
“His footsteps sounded hollow on the wooden stairs.”
3adjectiveface(of a face) Sunken, with the flesh fallen in.
“Her hollow cheeks made her look ten years older.”
4adjectiverealWithout real feeling, meaning or worth.
“It was a hollow apology and everybody in the room knew it.”
5nounsmallA small area of ground lower than the land around it.
“The village sits in a hollow between two hills.”
6verbholeTo make a hole or space inside something.
“They hollowed out a pumpkin and put a candle in it.”
Too few real examples of this word to estimate which sense is commonest.
Hollow comes from Old English holh, 'a hollow', through Proto-Germanic *hulwiją and the related *hulaz that also gives us hole, and behind them a Proto-Indo-European root *ḱel-, 'to cover, to hide'. Hole and hollow are one idea seen from two sides: the gap itself, and the thing with the gap in it.
Proto-Germanic
*hulwiją
Proto-West Germanic
*holh
Old English
holh — a hollow
Middle English
holow
English, today
hollow
From Middle English holow, holowe, holwe, holwȝ, holgh, from Old English holh (“a hollow”), from Proto-West Germanic holh, from Proto-Germanic hulwiją, from Proto-Germanic hulaz, from Proto-Indo-European ḱel- (“to cover, hide”). Cognate with Old High German huliwa and hulwa, Middle High German hülwe. Related to hole.
Etymology from Wiktionary, CC BY-SA