- Yedina
- Yeehaw Junction
- Yellow Dog
- Yemenia - Yemenia Airways
- yen note
- Yeni Cami
- Yeovil
- Yersinia arthritis
- Yersinia enterocolitica infection
- yersiniosis
- Yes
- Yes, Dear
- yeti lobster
- Yew Tree
- Yiewsley
- yin yang symbol
- yin-yang symbol
- Ylöjärvi
- Ymer Island
- Yoakum County
- Yoga Sutra
- Yoga Sutras
- Yoga Vasistha
- yoginis
- yocto...
- yoctoamp , yA
- yoctoampere , yA
- yoctometer , ym
- yoctometre , ym
- Yolanda and the Thief
- Yolo County
- Yolo telescope
- Yorba Linda
- Yorkville
- Yoruboid
- Yoruboid language
- Yoruboid languages
- Yoshida's sarcoma
- yotta...
- yottagram , Yg
- yottagramme , Yg
- yottahertz , YHz
- yottajoule , YJ
- yottameter , Ym
- yottametre , Ym
