triangle (n.)
- adultery
- affair
- amour
- battery
- bell
- bells
- bones
- castanets
- celesta
- chime
- clapper
- clappers
- clover
- cowbell
- crank
- cube
- cuboid
- cuckoldry
- cusp
- cymbals
- decagon
- deuce-ace
- dodecagon
- dodecahedron
- doorbell
- entanglement
- flirtation
- foursquare
- gamelan
- glockenspiel
- gnomon
- gong
- heptagon
- hexagon
- hexahedron
- icosahedron
- infidelity
- intrigue
- leash
- liaison
- lyra
- maraca
- marimba
- oblong
- octagon
- octahedron
- parallelepiped
- parallelogram
- pentagon
- pentahedron
- percussion
- pillory
- polygon
- polyhedron
- prism
- prismoid
- pyramid
- quadrangle
- quadrant
- quadrature
- quadrilateral
- rattle
- rectangle
- rhombohedron
- rhomboid
- rhombus
- romance
- rule
- ruler
- shamrock
- square
- stocks
- straightedge
- tam-tam
- tercet
- ternary
- ternion
- terzetto
- tetragon
- tetragram
- tetrahedron
- three
- threesome
- tierce
- tongue
- trapeze
- trapezium
- trapezoid
- treadmill
- trebuchet
- trefoil
- trey
- triad
- tricorn
- trident
- trilateral
- trilogy
- trimester
- trine
- trinity
- trio
- triplet
- tripod
- triptych
- trireme
- triskelion
- triumvirate
- trivet
- troika
- unfaithfulness
- vibes
- vibraphone
- xylophone
