What does posteriorly mean?
Posteriorly is an adverb meaning toward the back or rear of something. It is used particularly in anatomy, biology, medicine, and technical descriptions, where precise spatial relationships matter. For example, a speaker may describe a structure as extending posteriorly toward the spine or note that a muscle pulls a part backward. The word carries a formal, specialized tone and is less common in ordinary conversation, where backward or towards the back would usually be preferred. Its counterpart is anteriorly, meaning toward the front. Posteriorly is derived from posterior, an adjective meaning “situated behind” or “toward the rear,” and is especially useful when discussing the relative positions of parts of a body or organism. Although it can apply to objects in general, it is most familiar in anatomical and scientific contexts.
adverbToward or in the direction of the back or rear of something; at or near the posterior.
- In or toward the back or rear of an organism or object.
"The muscles of the tail contract to move the fish posteriorly."
"The sensor is positioned posteriorly, behind the main chamber."
"The surgeon moved the instrument posteriorly toward the patient's spine."
A word that keeps its spatial bearings straight: posteriorly points you toward the rear, while anteriorly points toward the front.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does posteriorly come from?
Posteriorly comes from the Latin adjective posterior, meaning “behind” or “toward the rear.” That word was the comparative form of posterus or post, terms associated with something coming after or lying behind. English borrowed posterior in the late 16th century, and the adverb posteriorly developed from it in the 19th century.
Related word forms
How posteriorly is actually used
This is a formal or technical term, especially common in anatomy, biology, medicine, and descriptive writing. In everyday English, backward or towards the back is usually clearer.
Easily confused with posteriorly
Posterior is normally an adjective meaning “at or toward the back,” while posteriorly is the adverb expressing that direction.