An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) To sink or plunge under water or beneath the surface of any enveloping medium.
2) To cover or overflow with water; immerse (Dictionary.com).

From L. submergere, from → sub- + mergere "to dip, immerse;" probably by rhotacism from PIE *mezg- "to dip, plunge;" cf. Skt. majj- "to sink in water;" Lith. mazgoju "to wash."

Marcidan, from Av. mraoc- "to float, submerge;" cf. Skt. mroc/mloc "to go down, set (of the Sun), to disappear, to hide;" Kurd., Laki, Nahâvandi, Bovir-Ahmadi mala- "swim," Kurd. melâna "ship, boat," melaq "wave" may be related to this Av. form.