- Trichorrhexis invaginata
- Trichorrhexis nodosa
- Trichosanthes
- Trichosanthes kirilowii
- Trichosanthin
- Trichoscopy
- Trichosporon
- Trichostatin a
- Trichothiodystrophy
- Trichotillomania
- Trichromacy
- Trichrome
- Trichrome stain
- Trichuriasis
- Trichuris
- Trichuris muris
- Trichuris suis
- Trichuris trichiura
- Tricin
- Tricine
- Triclabendazole
- Triclocarban
- Triclofos
- Triclopyr
- Triclosan
- Tricresyl phosphate
- Tricuspid atresia
- Tricuspid regurgitation
- Tricuspid valve
- Tricuspid valve stenosis
- Tricyclic
- Tricyclic antidepressant overdose
- Tricyclic antidepressants
- Tridimensional Personality Questionnaire
- Trier social stress test
- Triethanolamine
- Triethoxysilane
- Triethyl citrate
- Triethyl phosphite
- Triethylene glycol
- Triethylenemelamine
- Triethylenetetramine
- Trif
- Trifarotene
- Trifascicular block
- Triflate
- Triflic acid
- Trifluoperazine
- Trifluoroacetic anhydride
- Trifluoromethyl group
- Triflupromazine
- Trifluralin
- Trifluridine
- Triflusal
- Trifolium repens
- Trifunctional antibody
- Trigeminal autonomic cephalalgia
- Trigeminal autonomic cephalalgias
- Trigeminal ganglion
- Trigeminal lemniscus
- Trigeminal motor nucleus
- Trigeminal nerve
- Trigeminal neuralgia
- Trigeminal nucleus
- Trigeminal trophic syndrome
- Trigeminovascular system
- Trigger finger
- Trigger points
- Trigger zone
- Triglyceride lipase
- Triglycerides
- Trigone
- Trigonella foenum graecum
- Trigonelline
- Trigonocephaly
- Triheptanoin
- Trihexyphenidyl
- Trihydroxybenzoic acid
- Triiodide
- Triiodothyronine
- Trikafta
- Trilateral retinoblastoma
- Trilostane
- Trim24
- Trimalleolar fracture
- Trimebutine
- Trimer
- Trimesic acid
- Trimetazidine
- Trimethadione
- Trimethoprim
- Trimethoprim sulfamethoxazole
- Trimethylamine
- Trimethylamine N-oxide
- Trimethylaminuria
- Trimethylene carbonate
- Trimethylglycine
- Trimethylolpropane
- Trimethylsilane
- Trimethylsilyl chloride
- Trimethyltin chloride
- Trimetrexate
- Trimipramine
- Trimix
- Trimyristin
- Trinitrotoluene
- Trinucleotide repeat
- Trinucleotide repeat expansion
- Triol
- Triose phosphate isomerase
- Triosephosphate isomerase
- Trioxsalen
- Tripalmitin
- Triparanol
- Tripartite synapse
- Tripelennamine
- Tripeptide
- Tripeptidyl peptidase
- Tripeptidyl peptidase I
- Triphala
- Triphalangeal thumb
- Triphenylamine
- Triphenylene
- Triphenylethylene
- Triphosphatase
- Triple A syndrome
- Triple X syndrome
- Triple arthrodesis
- Triple helix
- Triple negative breast cancer
- Triple test
- Triple-A syndrome
- Triple-stranded DNA
- Triplegia
- Triplets
- Triploidy
- Tripod
- Tripod position
- Triprolidine
- Triptans
- Tripterygium wilfordii
- Triptolide
- Triptorelin
- Triquetrum bone
- Triradiate cartilage
- Tris
- Tris-buffered saline
- Trismus
- Trisomy
- Trisomy 13