lower limit; minimum
General term for the lowest allowable or possible value, often used in contrast with 上限 (upper limit).
The minimum age for this plan is 18.
Please set the lower temperature limit.
infimum
Mathematics term for the greatest lower bound of a set; technical use.
The infimum of this set is 0.
This system sets a lower age limit.
A warning is issued when the temperature falls below the lower limit.
The deal went through because the price exceeded the lower limit.
It's a system that places an order once stock reaches the lower limit.
最小値 is the mathematical 'minimum value' actually attained by a set, while 下限 (infimum) is the greatest lower bound, which may not be reached.
最低 is a general adjective/noun for 'lowest' or 'worst', whereas 下限 specifically names the lower boundary value of a defined range.
Compound of 下 (lower) and 限 (limit). The reading かげん follows standard on'yomi.