As nouns the difference between diametre and length

is that diametre is alternative form of diameter while length is the distance measured along the longest dimension of an object.

As a verb length is

to lengthen.

As nouns the difference between cup and cop

is that cup is cup while cop is plait, braid (of hair).

As a verb cup

is to not attend a course, a class without permission of the teacher or cup can be to temporarily or permanently cease to provide (electricity or water supply) or cup can be to switch off (a breaker or fuse).

As nouns the difference between urchin and foundling

is that urchin is a mischievous child while foundling is an abandoned child, left by its parent(s), often a baby left at a convent or similar safe place.

As nouns the difference between taxonomy and rendition

is that taxonomy is the science or the technique used to make a classification while rendition is the surrender (of a city, fortress etc.).

As a verb rendition is

to surrender or hand over (a person or thing); especially, for one jurisdiction to do so to another.

As an adjective stupid

is lacking in intelligence or exhibiting the quality of having been done by someone lacking in intelligence.

As an adverb stupid

is (slang|dated) extremely.

As a noun stupid

is a stupid person; a fool.

As a verb sumit is

.

Eqation is likely misspelled.

Eqation has no English definition.

As a noun formula is

any mathematical rule expressed symbolically.

As a verb beheld

is (behold).

As a noun host is

autumn (season).

In lang=en terms the difference between restrain and forbear

is that restrain is   to restrict or limit while forbear is to control oneself when provoked.

As verbs the difference between restrain and forbear

is that restrain is   to control or keep in check while forbear is to keep away from; to avoid; to abstain from; to give up.

As a noun forbear is

.

As nouns the difference between taxonomy and budgeter

is that taxonomy is the science or the technique used to make a classification while budgeter is one who budgets.

As a noun taxonomy

is the science or the technique used to make a classification.

As a proper noun forth is

a river in scotland that flows for about 47 km (29 miles) from the trossachs through stirling to the firth of forth on the north sea or forth can be an imperative, stack-based high-level programming language.