The actual meaning of this incision is unknown; it could be the Tau/Tav/Taw letter of the Paleo-Hebrew alphabet, a figurative representation of an "X", or or some other schematic figure.

Measurements:

• Incision length:  5/8" (16 mm)
• Incision width:  1/2" (12 mm)
• Maximum jar-fragment diagonal:  4 3/16" (107 mm)
• Handle-loop opening:  1 1/2 x 1" (38 x 25 mm)
• Jar-body thickness:  3/16-1/4" (4-6 mm)

The third incision--a single line midway along the handle's loop--may have been incised at the same time as the plus-mark, possibly as the original location desired, or it could be an unintentional stray mark (ancient, or more recent).

Note:  This is not a Type-484 LMLK jar-handle (some bearing similar post-fired Plus marks), but a much smaller style.