安固 is read as あんこ (anko) and means secure.
あんこ
anko
あき
Aki (former province located in the west of present-day Hiroshima Prefecture)
あんぜんちたい
safety zone
あんぜんそうち
safety device
あんていてき
stable
あんきょう
Road Safety Association (abbr.)
あんぜんせっけいようけん
safety design requirement
あんぜんかんり
safety administration
あんていたいりく
stabilized continent
あんぜんいき
safety margin
あんどうけん
safe conduct (right)
あんざんがた
right physique for an easy delivery
あんぜんたい
safety belt (typically used in Japanese construction work)