upsilon

As nouns the difference between upsilon and null

is that upsilon is the twentieth letter of classical]] and modern greek; the twenty-second letter of [[old greek|old and ancient greek while null is zero, nil; the cardinal number before einn.

As nouns the difference between epsilon and upsilon

is that epsilon is the name for the fifth letter of the Greek alphabet, ε or Ε, preceded by delta (Δ, δ) and followed by zeta (Ζ, ζ) while upsilon is the twentieth letter of Classical and Modern Greek; the twenty-second letter of Old and Ancient Greek.

As a noun upsilon

is the twentieth letter of classical]] and modern greek; the twenty-second letter of [[old greek|old and ancient greek.

As an adjective hypsiloid is

(anatomy) resembling the greek letter upsilon.