Strong's H4565מִסְתָּר: properly, a concealer, i.e. a covert KJV:secret(-ly, place).
Meanings: Brown-Driver-Briggs (1906) and Strong's Hebrew Dictionary (1890), public domain, via the Open Scriptures Hebrew Bible Project (CC BY 4.0). TWOT numbers for reference only.
Root family 1551: סָתַרsātar — hide, conceal; hide oneself, be hid; carefully hide, shelter; love carefully concealed; hide oneself carefully; be absent, keep close, secret