Hiddekel

Boyd’s Bible Dictionary:

(rapid). Third river of Eden, no doubt Tigris (Gen. 2:14; Dan. 10:4).

Concise Bible Dictionary:

One of the rivers of Eden: supposed to be identical with the Tigris, which is called Dijlah (Gen. 2:14; Dan. 10:4).

Strong’s Dictionary of Hebrew Words:

Number:
2313 (find all occurrences in KJV Bible)
Transliteration:
Chiddeqel
Phonic:
khid-deh’-kel
Meaning:
probably of foreign origin; the Chiddekel (or Tigris) river
KJV Usage:
Hiddekel

Jackson’s Dictionary of Scripture Proper Names:

riddle of the (date) palm: riddle of lightness

Potts’ Bible Proper Names:

Quick flowing; an influx; sharp voice or sound:―one of the rivers of Eden, Gen. 2:14. {Celeriter fluens}