Category:3 (number)

• Trilogies‎ (3 C, 12 P)
• Trios‎ (8 C, 54 P)

B

• Three-base-unit banknotes‎ (3 F)
• Border tripoints‎ (4 C, 64 P)

C

• Ternary computers‎ (1 C, 10 P)

D

• Triple deities‎ (4 C, 4 P)

F

• 3-folds‎ (15 P)

M

• Medical triads‎ (1 C, 51 P)

N

• Three-volume novels‎ (7 P)

O

• Ternary operations‎ (8 P)

P

• Three Pilgrimage Festivals‎ (4 C, 3 P)

R

• Three Rebellions in Shouchun‎ (14 P)
• Three-wheeled robots‎ (1 C, 3 P)

S

• Triple stars‎ (1 C, 50 P)

T

• Three-dimensional coordinate systems‎ (19 P)
• Triangles‎ (6 C, 30 P)
• Tridents‎ (1 C, 8 P)
• Trilateral relations‎ (4 C, 16 P)
• Trimers (chemistry)‎ (1 C, 2 P)
• Trinitarianism‎ (9 C, 52 P)

V

• Volume‎ (7 C, 27 P)

• 3

B

• Balanced ternary floating point
• Beck's cognitive triad
• Beck's triad (cardiology)

D

• Dark triad

I

• III

L

• Law of trichotomy

M

• Macdonald triad
• Ménage à trois

P

• Tripedalism
• Pi is 3
• Power of three

T

• Ternary floating point
• Tertium quid
• Third (chord)
• Third circle of hell
• Three Brothers (jewel)
• Three-dimensional space
• Threesome
• Tri-
• Triad
• Triad (American fraternities)
• Triad (computing)
• Triad (monitors)
• Triad (music)
• Triad (religion)
• Triadization
• Trial (number)
• Trichotomy (philosophy)
• Trident
• Trion (geometry)
• Triple
• Triple (baseball)
• Triple (mathematics)
• Triple Alliance (1788)
• Triple-headed eagle
• Triplet lens
• Tripolis (region of Phoenicia)
• Tritheism
• Triumvirate (ancient Rome)

Y

• Year of the Three Emperors