From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

En-Tappuah . A place on the boundary of Manasseh (  Joshua 17:7 ). Generally identified with a spring near Yâsûf , in a valley to the S. of Mukhna, which drains into Wady Kanah. The place is probably the Tappuah (wh. see) of   Joshua 16:8;   Joshua 17:8 .

Smith's Bible Dictionary [2]

En-tap'puah.  Joshua 17:7. See Tappuah .

Holman Bible Dictionary [3]

 Joshua 17:7Tappuah

International Standard Bible Encyclopedia [4]

en - tap´ū̇ - a , en - ta - pū´a ( עין תּפוּח , ‛ēn tappūaḥ  ; πηγὴ Θαφθώθ , pēgḗ Thaphthō̇th , "apple spring"): Probably in the land of Tappuah which belonged to Manasseh, although Tappuah, on the border of Manasseh, belonged to Ephraim ( Joshua 17:7 f). It lay on the border of Ephraim which ran southward East of Shechem, and is probably to be identified with the spring at Yāsūf , about 3 miles North of Lebonah.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [5]

(Hebrews Eyn Tappu'ach, עֵין תִּפּוּחִ ) , Fountain Of Tappuah; Sept. Πηγὴ Θαπφουέ v.r. Θαφθώθ ), a spring near the city Tappuah (q.v.), put for that place in  Joshua 17:7 (comp.  Joshua 17:8).