cleavage

Mineral cleavage is a property of cohesion. The cleavage of the particles themselves and its attitude with reference to the plane of the greatest and mean dimensional axes help to determine the perfection of rock cleavage. The more nearly parallel to the greater dimensions of the particle, and the better the mineral cleavage, the better the rock cleavage produced.

Low-cut Restoration costumes worn by the Misses Lockwood and Roc (see cut) display too much "cleavage" (Johnston Office trade term for the shadowed depression dividing an actress' bosom into two distinct sections).

Half an hour later, she was staring at a large bottom-cleavage, which was protruding from under the bed. / 'Ohhh Kayyy. Here we go. This is basically your problem.' / Olivia took a few steps back as the bottom-cleavage started wriggling out towards her. Connor the counter-surveillance expert pulled himself awkwardly to his knees, […]

[C]itellate annelids (leeches + oligochaetes) provide solid ground for comparative analyses, because they form a monophyletic group within the paraphyletic polychaetes[…]. […] The unequal cleavage of the zygote followed by the unequal cleavage of the CD cell is critical for D-quadrant specification since the cytoplasmic determinants present in teloplasm are segregated to the larger CD cell at first asymmetric cleavage and then to the larger D cell at the second asymmetric cleavage[…].

Carotenoid cleavage oxygenases (CCOs) are a class of enzymes that oxidatively cleave carotenoids into apocarotenoids. Carotenoid cleavage oxygenases have been identified in plants and animals and produce a wide range of cleavage products. […] Two of the three enzymes showed cleavage of β, β-carotene at the 9,10 and 15,15' position, respectively.

Notice that cleavage has nothing to do with imperfections in the crystal. Indeed, if you try cleaving an imperfect crystal, you may find that it cannot be cleaved as well as a perfect one. The cleavage is the result of the orderliness of the atomic arrangement. No wonder imperfections, which disturb the orderliness, disturb the cleavage as well. You will also note that the cleavage directions are obedient to the symmetry of the crystal.

A voting bloc in Congress can represent a long-standing alliance or can be created anew as a result of the increased saliency of a particular issue, such as war or a severe economic downturn. A division between voting blocs is called a cleavage and because voting blocs are impermanent, dominant cleavages are always changing.