Perhaps remotely from the same as basis (through the notion of going to the bottom); a touch-stone, i.e. (by analogy) torture -- torment.
see GREEK basis
a. the touchstone (called also basanite, LatinlapisLydius), by which gold and other metals are tested.
b. the rack or instrument of torture by which one is forced to divulge the truth.
c. torture, torment, acute pains: used of the pains of disease, Matthew 4:24; of the torments of the wicked after death, ἐν βασάνοις ὑπάρχειν, Luke 16:23 (Wis. 3:1; 4 Macc. 13:14); hence, ὁ τόπος τῆς βασάνου is used of Gehenna, Luke 16:28. (In Greek writings from (Theognis), Pindar down.)