Here are definitions of the three main words you mentioned:
- aĵo — thing or substance (of a vague kind)
- esto — the state of being, existence, presence
- estaĵo — a being, thing that exists (usually a living thing)
Kio estas tiu aĵo? What is that thing?
Mi ĝojas ke mia esto utilas. I am glad that my existence/being here is useful.
La titolo de la libro estas "Esto kaj Tempo." The title of the book is "Being and Time."
De antaŭ semajno, mi ne parolas al alia homa estaĵo. I have not spoken to another human being in a week.
Here are three other very common related words:
Tio dependos de via estado dum la konferenco. That will depend on your presence during the conference.
Ŝia ĉeesto tie surprizis min. Her presence there surprised me.
Mi eĉ ne suspektis la ekziston de frato. I did not even suspect the existence of a brother.
A lignaĵo is a wooden thing (ligna objekto). Lignesto is the state of being wooden (esto ligno). Bovaĵo is beef (bova viando). Bovesto is the state of being a cow (esto bovo). The suffix -aĵo is a shortcut: it has no very specific meaning beyond "thing or substance" and common sense has to be used when interpreting it in context: for example, araneaĵo (spider-thing) is "a spider web", not spider-meat, while infanaĵo is "a childish thing", which could be a toy or a childish idea or action. Similarly, you have bonaĵo (a good thing), ĉirkaŭaĵoj (surroundings), kre(it)aĵo (creature), konstruaĵo (building), etc.
I cannot easily interpret the other words you came up with, but estoligno seems to mean "wood of/for being", estolignaĵo means "wooden thing of/for being", estaĵoligno means "wood from a being", and lignestaĵo means "wooden being." They are correctly constructed words, but they sound like something from a wizard's spellbook, or an esoteric work.
