As a proper noun underground

is (uk|rail transport) the london underground.

As an adjective hypogean is

existing or growing underground.

As a proper noun underground

is (uk|rail transport) the london underground.

As a noun hypogee is

hypogeum.

As nouns the difference between cellar and hypogee

is that cellar is an enclosed underground space, often under a building; used for storage or shelter or cellar can be salt cellar while hypogee is hypogeum.

As a verb cellar

is to store in a cellar.

As nouns the difference between vault and hypogee

is that vault is an arched structure of masonry, forming a ceiling or canopy or vault can be an act of vaulting; a leap or jump while hypogee is hypogeum.

As a verb vault

is to build as, or cover with a vault or vault can be (ambitransitive) to jump or leap over.

As nouns the difference between heartwood and agarwood

is that heartwood is the wood nearer the heart of a stem or branch, different in color from the sapwood while agarwood is a type of heartwood from aquilaria trees, created when the trees become infected with mold and begin to produce an aromatic resin in response to this attack.

As a proper noun aquilaria

is .

As a noun agarwood is

a type of heartwood from aquilaria trees, created when the trees become infected with mold and begin to produce an aromatic resin in response to this attack.

As a verb infected

is past tense of infect.

As an adjective infected

is referring to something that has received an infection.

As a noun agarwood is

a type of heartwood from Aquilaria trees, created when the trees become infected with mold and begin to produce an aromatic resin in response to this attack.

As nouns the difference between resin and agarwood

is that resin is a viscous hydrocarbon secretion of many plants, particularly coniferous trees while agarwood is a type of heartwood from aquilaria trees, created when the trees become infected with mold and begin to produce an aromatic resin in response to this attack.

As a verb resin

is to apply resin.

In rare|lang=en terms the difference between heptagram and heptangle

is that heptagram is (rare) a heptagon while heptangle is (rare) a heptagon.

As nouns the difference between heptagram and heptangle

is that heptagram is either of two regular seven-pointed stars, drawn with the construction lines retained; a heptangle while heptangle is (occult) a seven-pointed star with the construction lines retained.

As nouns the difference between heptagon and heptangle

is that heptagon is heptagon while heptangle is (occult) a seven-pointed star with the construction lines retained.