(idiomatic) In a situation which is unsuitable, unfamiliar, or unenjoyable.

(genetics) A kind of genetic material, found in all organisms, that can move around within a genome, or be transferred from one species or replicon to another.

Alternative form of rare earth element

A model that uses simplified description of behavior of spatially distributed physical system into a topology which consists of discrete entities that approximate the behavior of the distributed system under certain assumptions.

(HTML) An HTML element that normally begins on a new line, and may or may not contain other block level elements or inline elements.

(inorganic chemistry, physics) Any chemical element from the main group.

(chemistry) Any of a group of seventeen soft, lustrous, sometimes magnetic metals that form trivalent salts; they include the lanthanides plus yttrium, scandium, thorium and sometimes zirconium.

(chemistry) A systematic name for an element, derived from the digits of its atomic number to which the suffix -(i)um is appended; normally only used for transuranic elements before or for a short period after they have been created, after which they will be given a non-systematic name.

Any part of a mechanism that exercises some form of logical control, such as a ratchet, trip, detent or interlock.

plural of systematic element name.