[ rahy-buh-sohm ]

nounCell Biology.
  1. a tiny, somewhat mitten-shaped organelle occurring in great numbers in the cell cytoplasm either freely, in small clusters, or attached to the outer surfaces of endoplasmic reticula, and functioning as the site of protein manufacture.

Origin of ribosome

First recorded in 1955–60; ribo(se) + -some3

Other words from ribosome

  • ri·bo·so·mal, adjective

Words Nearby ribosome

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use ribosome in a sentence

British Dictionary definitions for ribosome


/ (ˈraɪbəˌsəʊm) /

  1. any of numerous minute particles in the cytoplasm of cells, either free or attached to the endoplasmic reticulum, that contain RNA and protein and are the site of protein synthesis

Origin of ribosome

C20: from ribo (nucleic acid) + -some ³

Derived forms of ribosome

  • ribosomal, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for ribosome


[ bə-sōm′ ]

  1. A sphere-shaped structure within the cytoplasm of a cell that is composed of RNA and protein and is the site of protein synthesis. Ribosomes are free in the cytoplasm and often attached to the membrane of the endoplasmic reticulum. Ribosomes exist in both eukaryotic and prokaryotic cells. Plastids and mitochondria in eukaryotic cells have smaller ribosomes similar to those of prokaryotes. See more at cell.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for ribosome


[ (reye-buh-sohm) ]

A small, ball-like structure in the cell, made of proteins and RNA molecules, that serves as a platform on which the cell's proteins are made.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.