The difference between Colossal and Giant

When used as adjectives, colossal means extremely large or on a great scale, whereas giant means very large.

Giant is also noun with the meaning: a mythical human of very great size.

check bellow for the other definitions of Colossal and Giant

Colossal as an adjective:

Extremely large or on a great scale.

Examples:

"A single puppy can make a colossal mess."

Giant as a noun:

A mythical human of very great size.
Giant as a noun (mythology):

Specifically, any of the gigantes, the race of giants in the Greek mythology.
Giant as a noun:

A very tall person.
Giant as a noun:

A tall species of a particular animal or plant.
Giant as a noun (astronomy):

A star that is considerably more luminous than a main sequence star of the same temperature (e.g. red giant, blue giant).
Giant as a noun (computing):

An Ethernet packet that exceeds the medium's maximum packet size of 1,518 bytes.
Giant as a noun:

A very large organisation.

Examples:

"The retail giant is set to acquire two more struggling high-street chains."
Giant as a noun:

A person of extraordinary strength or powers, bodily or intellectual.
Giant as a noun:

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