The prefix appears at the beginning of a medical term and adds meaning to the root word, like adjectives add meaning to nouns in the English language.

Prefixes often indicate:

• Number, such as bi-, meaning “two”
• Position, such as sub-, meaning “under”
• Direction, such as intra-, meaning “within”
• Time, such as brady-, meaning “slow”
• Negation, such as a- and an-, meaning “without”

Common Prefixes

Here is a list of commonly used prefixes. It is helpful to memorize these common prefixes as you build your knowledge of medical terminology:

• a-, an-: Absence of, without, not
• ab-: Away from, take away
• ad-: Towards, to, near
• ambi-, ambo-: Both
• amphi-: Double, both sides
• ana-: Up, apart
• ante-: Before, in front of, forward
• anti-: Opposing, against
• ap-, apo-: Separated, derived from
• aut-, auto-: Self, by yourself
• bi-: Double, two, twice, both
• brachy-: Short
• brady-: Slow
• cata-: Lower, down, against
• circum-: Around
• co-, con-, com-: Together, with
• contra-: Against, opposed to
• de-: Down, from
• di-: Twice, two
• dia-: Through, apart, across, between
• dis-: Apart from, free from
• dys-: Bad, painful, difficult
• e-, ec-, ex-: From, away from, out of
• ect-, exo-, ecto-: Outside, outer, on
• em-, en-: In
• end-, endo-, ent-, ento-: Within, inner
• epi-, ep-: Upon, over, on
• eu-: Normal
• extra-, extro-: Beyond, outside of, outward
• hemi-, semi-: Half, half of
• hyper-: Above, excessive, beyond
• hyp-, hypo-: Below, beneath, deficient
• im-, in-: Intro, in, within
• infra-: Below, beneath
• inter-: Between
• intra-: Within, inside
• intro-: Into, within
• iso-: Same, equal
• macro-: Large
• mal-: Bad
• mes-, meso-: Middle
• meta-: Beyond, changing
• micro-, micr-: Tiny, small
• mono-, uni-: One
• mult-, multi-: Many, multiple
• neo-: New, recent
• nulli-: None
• oligo-: Small amount
• ortho-: Straight, normal
• pan-: All
• para-: Beyond, beside, after
• per-: Through
• peri-: Around
• poly-: Many, excessive
• post-: After, following, behind
• pre-, pro-: In front of, before, preceding
• presby-: Old age
• pseudo-: False
• quadri-: Four
• re-: Backward, again
• retro-: Behind, backward
• semi-: Half, partial
• sub-: Under, beneath
• super-, supra-: Above, excessive, superior
• sym-, syn-: With, together
• tachy-: Rapid, fast
• trans-: Through, across
• tri-: Three
• ultra-: Excessive, beyond
• uni-: One

See the following box for examples of commonly used prefixes in body-related medical terms. Additional prefixes will be discussed in each chapter related to specific body systems.