simplex

Word family

• simplicity
  nounB2
• simple
  adjectiveA2
• simply
  adverbB1
• simplify
  verbB2
• simplification
  nounC1

Synonym discussion

Sense: adjective/1

Simplex, simple, single, unitary, and elementary all relate to the idea of 'not complex,' but they differ in register and scope. Simple is the everyday word (a simple question) and covers anything easy or uncomplicated. Single focuses on number rather than lack of complexity (a single page). Unitary is more formal and appears in technical descriptions of systems that function as one whole (a unitary state). Elementary implies the most basic or introductory level (elementary school). Simplex is the most technical of the group; it describes something built from exactly one part or element, not just something that is easy to understand. For example, you would call a cell with a single nucleus simplex rather than simple — because 'simple' would sound too informal in a biological description.

Common collocations

Etymology

Simplex comes directly from Latin 'simplex,' meaning 'single, simple, plain.' This Latin word is formed from 'semel' (once) and 'plicare' (to fold), so its literal sense is 'folded once' — a single layer without complication. English borrowed the word in the 1500s. In the 20th century, engineers adopted it for communication systems that work in one direction at a time, and mathematicians used it for the simplest geometric shape in any number of dimensions.