As a noun magnesium

is magnesium.

As an adjective ferromagnesian is

that contains both iron and magnesium.

Homocystinuria is a related term of cystinuria.

In medicine terms the difference between cystinuria and homocystinuria

is that cystinuria is the presence of cystine in the urine while homocystinuria is an inherited metabolic disorder characterised by the presence of homocysteine in the urine.

As adjectives the difference between lethal and cytolethal

is that lethal is deadly; mortal; fatal while cytolethal is that is lethal to cells.

As a noun lethal

is one of the higher alcohols of the paraffine series obtained from spermaceti as a white crystalline solid.

As a noun cell

is a single-room dwelling for a hermit or cell can be (us|informal) a cellular phone.

As a verb cell

is to place or enclose in a cell.

As an adjective cytolethal is

that is lethal to cells.

Demersal is a synonym of benthic.

As adjectives the difference between benthic and demersal

is that benthic is pertaining to the benthos; living on the seafloor, as opposed to floating in the ocean while demersal is that lives near the bottom of a body of water.

Planktonic is an antonym of demersal.

As adjectives the difference between planktonic and demersal

is that planktonic is of or pertaining to plankton while demersal is (biology) that lives near the bottom of a body of water.

As a noun cusp

is a sharp point or pointed end.

As an adjective cuspy is

having cusps.

As nouns the difference between cystine and cystinuria

is that cystine is while cystinuria is (medicine) the presence of cystine in the urine.

As nouns the difference between urine and cystinuria

is that urine is urine while cystinuria is (medicine) the presence of cystine in the urine.

Cystinlysinuria is a related term of cystinuria.

As a noun cystinuria is

(medicine) the presence of cystine in the urine.