Outermost of the three tissue layers in the embryo of a metazoan animal. Through development, it will produce the epidermis (skin) and nervous system of the adult.
A microscopic double layer of lipids and proteins forming the boundary of cells or organelles.
A flexible or semiflexible covering or waterproofing whose primary function is to exclude water.
A mechanical, thin, flat flexible part that can deform or vibrate when excited by an external force.
A piece of parchment forming part of a roll.