Philosophical underpinnings: Everything in the universe is made up of "actions". (We can discuss Quantum Mechanics when you learn enough Esperanto for a discussion. :) Some of these actions seem solid and/or stable, so to simplify our lives we call them "things".

As language users, to discuss anything, humans use words. Almost all the words we use are:

what kind of word:	this is what grammarians call them:
action - like to love, to fly, to beautify	verb
thing - like bird, Fred, beauty	noun
word describing a "thing" - like big, blue, quiet, beautiful	adjective
word describing an "action" - like rapidly, beautifully	adverb
word describing another describing word	unfortunately, also called adverbs
word that connects words	conjunctions and prepositions
word that replaces the name of a "thing" - "i", "you", "it", etc.	pronouns
hey! words that yell	interjections