Concentration; strength
Sexual virility: the ability to become erect or achieve orgasm.
Potentiality, ability, capacity.
Power, authority.
The ability or capacity to perform something
That which gives strength or in which strength consists; a supporting factor or member; mainstay.
A cord or tendon of the body.
A cord or string, particularly (music) as of a musical instrument.
Muscular power, muscle; nerve, nervous energy; vigor, vigorous strength.
To knit together or make strong with, or as if with, sinews.