sempiternally

As a noun taxonomy

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

As an adverb sempiternally is

in a sempiternal manner; eternally.

As adverbs the difference between timelessly and sempiternally

is that timelessly is in a timeless manner while sempiternally is in a sempiternal manner; eternally.

As adverbs the difference between eternally and sempiternally

is that eternally is for eternity; forever while sempiternally is in a sempiternal manner; eternally.

As an adjective everlasting

is lasting or enduring forever; existing or continuing without end; immortal; eternal.

As a noun everlasting

is an everlasting flower.

As an adverb sempiternally is

in a sempiternal manner; eternally.