Where we going Rick?
I was reading and teaching my kids some stuff and ran into this question, well now my kids want to build a small Ark and i am supposed to help. So I had some questions.
Wikipedia, definition just scratches the surface.
Most modern English versions of the Bible translate it as "cypress." This is probably incorrect and is really only a guess supported by very weak evidence. Why cypress? In trying to solve the identity of "gopher wood," some guessed that a transliteration might be involved ("kupar" into “gopher”). Adam Clarke's Commentary says, "supposing the Greek word kuparissov, cypress, was formed from the Hebrew rpg, gopher; for take away the termination issov, and then gopher and kupar will have a near resemblance." Another supposed evidence for “cypress” is based on the fact that cypress trees are large and strong, and in the post-Flood earth, at least, once grew abundantly in Chaldea and Armenia. Armenia is where the ark is believed to have landed, in the mountains of Ararat.
Cypress is far from the only guess made by translators. Other trees and plants include pine, cedar, fir, ebony (Bockart), wicker (Geddes), juniper (Castellus), acacia (Religious Tract Society), boxwood, or slimed bulrushes (Dawson).