flat (adj) simple 4 realizations
ACCEPTED Realization 1
type Polysemy
language Ancient Greek
lexeme afeles
meaning 1 flat, smooth
direction
meaning 2 simple, easy
reference
comment
ACCEPTED Realization 2
type Polysemy
language Classical Arabic
lexeme basīṭ-
meaning 1 expanded and even, wide, spacious

بَسَطَ المَكَانُ القَوْمَ (basaṭa l-makānu l-qawma)


The place was sufficiently wide, or ample, for the people, or company of men.

direction
meaning 2 simple, uncompounded (in philosophy))

بسائط العلم (basāˀiṭu l-ˁilmi)


basic scientific questions

reference BK: I 126 Lane: 204
comment The verb بَسَطَ  is used, metaphorically, as relating to anything which cannot be conceived as composed or constructed. And sometimes it denotes giving liberally or bountifully. 
ACCEPTED Realization 3
type Polysemy
language Classical Arabic
lexeme sahl-
meaning 1 smooth, plain or level ʔarḍ- sahlat- 

plain or level tract of land

direction
meaning 2 easy sahl-u l-maḳādat-i 

easy to be led

reference Lane: 1453
comment
ACCEPTED Realization 4
type Borrowing
language 1 French
language 2 English
lexeme 1 plane
lexeme 2 plain
meaning 1 flat, even

une zone plane


a flat area

direction
meaning 2 simple, common in plain words

in simple words

reference <personally collected data>
comment The meaning of the French word has become obsolete.