下限 is read as かげん (kagen) and means infimum.
かげん
kagen
じょうげげん
bounds
うぃんどうかげん
lower window edge
かげんかかく
price floor
かりゅう
lower classes
かこう
descent
げしゅく
boarding house
しもはんき
second half of the year
したしらべ
preliminary investigation
げだん
low position (of a sword in kendo, etc.)
かき
the following
したくさ
undergrowth
げらく
depreciation