Definition of PLACOID. : of, relating to, or being a scale of dermal origin with an enamel-tipped spine characteristic of the elasmobranchs. ADVERTISEMENT.Greek plak-, plax flat surface.First Known Use: 1842.efinition of PLACOID. : of, relating to, or being a scale of dermal origin with an enamel-tipped spine characteristic of the elasmobranchs. ADVERTISEMENT. Greek plak-, plax flat surface. First Known Use: 1842.
A tree pruner is a class 1 lever. The fulcrum is where the two blades cross, and the load is what you are cutting. The effort is applied to the two handles.
Poplar is a closed-grain hardwood that has many uses. Poplar is a type of wood that is commonly used to make furniture, wood toys, moldings and paneling.ecause of this, there may be some confusion as to why poplar wood is considered a âhardwood.â Since the yellow poplar is a deciduous tree â meaning that the tree sheds its leaves annually â the wood from the yellow poplar is considered to be a hardwood rather than the âsoftwoodsâ that evergreen trees produce.