seif

• saif

From Arabic سَيْف (sayf, “sword”). Doublet of xiphos.

seif (plural seifs)

1. A sand dune that elongates parallel to the prevailing wind.
   • 1954, Bulletin of the Research Council of Israel, volume 4, page 196:

     Such seifs have a somewhat zig-zag form instead of a fairly straight line.
     On the top of seifs small transverse dunelets are very often found, and these may be likened to almost straightened-out barchans. […] On the top of the seif they form a wave-like pattern with a fairly defined "wavelength".

   • 1973, Ralph Alger Bagnold, The Physics of Blown Sand and Desert Dunes, page 224:

     Though the actual transition forms suggested in Fig. 76 do exist and have been examined by the author, the above tentative explanation of the growth of a seif dune chain should certainly not be taken as implying that all such chains have originated as barchans.

   • 1980, P. Turner, Continental Red Beds, page 80:

     Seifs are longitudinal forms elongated parallel to the prevailing wind direction.

   • 2009 February 26, Bruno Andreotti et al., “Giant aeolian dune size determined by the average depth of the atmospheric boundary layer”, in Nature, volume 457, number 7233, →DOI, pages 1120–1123:

     Tsoar, H. Dynamic processes acting on a longitudinal (seif) sand dune .

• longitudinal dune

• Dune on Wikipedia.Wikipedia

• EFIs, Feis, ISEF, ISFE, feis, fise

• seid

Latin sitis.

seif oblique singular, m (nominative singular seis)

1. thirst

Borrowed from English safe.

seif n (plural seifuri)

1. safe box