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.
Prunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, nectarines, apricots and almonds. Around 430 species are spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament. The fruit from this genus are commonly called the stone fruit.