am- amb- = around am-putate amb-ient to cut around. going around.
ante- anti- = before ante-cedent anti-cipate going before. to take before.
bi- bis- = two or twice bi-ped bis-cuit a two-footed animal. twice cooked.
circum- circu- = around circum-navigate circu-it to sail around. journey around.
con- co- co- col- com- cor- = with or together con-vene co-equal co-gnate col-loquy com-pose cor-relative to come together. equal with. born together. a speaking with another. to put together. relative with.

NOTE.—The forms co-, col-, com-, and cor-, are euphonic variations of con-.

contra- contro- counter- = against contra-dict contro-vert counter-mand to speak against to turn against to order against
de- = down or off de-pose; de-fend to put down; fend off.
dis- di- dif- asunder = apart opposite of dis-pel di-vert dif-fer to drive asunder. to turn apart. to bear apart; disagree.

NOTE.—The forms di- and dif- are euphonic forms of dis-; dif- is used before a root beginning with a vowel.

ex- e- ec- ef- = out or from ex-clude e-ject ec-centric ef-flux to shut out. to cast out. from the center. a flowing out.

NOTE.—e-, ec-, and ef- are euphonic variations of ex-. When prefixed to the name of an office, ex- denotes that the person formerly held the office named: as, ex-mayor, the former mayor.

extra- = beyond extra-ordinary beyond ordinary.
in- il- im- ir- en-, em- (in nouns and verbs) = in, into, on in-clude il-luminate im-port ir-rigate en-force to shut in. to throw light on. to carry in. to pour water on. to force on.

NOTE.—The forms il-, im-, and ir- are euphonic variations of in-. The forms en- and em- are of French origin.

in- i(n) il- im- ir- (in adjectives and nouns.) = not in-sane i-gnoble il-legal im-mature ir-regular not sane. not noble. not legal. not mature. not regular.
inter- intel- = between or among inter-cede intel-ligent to go between. choosing between.
intra- = inside of intra-mural inside of the walls.
intro- = within, into intro-duce to lead into
juxta- = near juxta-position a placing near
non- = not non-combatant not fighting.

NOTE.—A hyphen is generally, though not always, placed between non- and the root.