Lexical Definition

‎στοιβάς‎ stoibás (stoy-bas') leafy branch ^G:N-F
from a primary (to "step" or "stamp")

branch.

• a spread (as if tramped flat) of loose materials for a couch, i.e. (by implication) a bough of a tree so employed

Abbott-Smith

στοιβάς, v.s. στιβάς.

Liddell-Scott-Jones

στοιβάς, στιβάς, άδος, ἡ,

(στείβω) bed of straw, rushes, or leaves, whether strewn loose [NT], or stuffed into a mattress, [Refs 5th c.BC+]

__b straw strewn at a sacrifice, hence as name of the ceremony, [Refs 2nd c.AD+]
__2 mattress, [Refs 5th c.BC+]; especially one used by soldiers, [Refs 5th c.BC+]
__3 generally, bed, [Refs]
__4 nest or lair of mice, [Refs 4th c.BC+]; of the fish φυκίς, [Refs 4th c.BC+]
__5 grave, [Refs]

_{LSJ Scripture Refs: Mark.11.8}