extra/extro

outside, beyond

Spelled extra, extro · Latin extra 'outside, beyond'; extro- is a later reshaping modeled on intro-.

Latin extra meant outside: extraneous details fall outside the subject, extravagant spending wanders beyond limits, and an extrovert turns outward.

Words built from it

extraneous — Unrelated to what matters or is needed.
Latin extra (outside) → extraneus (external, foreign) → extraneous
extrapolate — Estimate beyond known information by extending its pattern.
extra- (beyond) + -polate, borrowed from interpolate (estimate between known values)
extravagant — Spending or using far more than is reasonable.
Latin extra (beyond) + vagari (wander) → extravagari (wander outside) → extravagant
extrovert — A person who tends to seek social interaction and outward activity.
Latin extra (outside) + vertere (turn) → extravert → extrovert, reshaped under the influence of introvert
extraordinary — Very unusual or remarkable.
Latin extra (outside) + ordinem (order) → extraordinarius (outside the usual order) → extraordinary
extracurricular — Outside the regular course of school studies.
extra- (outside) + curricular (relating to a course of study), from Latin curriculum (course)
extrasensory — Said to involve perception beyond the ordinary senses.
extra- (beyond) + sensory (relating to the senses), from Latin sensus (perception)

extraction — From Latin ex- (out) + trahere (pull), through extractus. Its opening letters cross the boundary between ex- and tract-.