The first term determines the nature of the drug's effect and how much drug is needed at the site of action to engage that site to a clinically meaningful extent in the usual patient. The second term in the equation determines the magnitude of the drug's effect by determining how much drug reaches the site of action.
Tsuki (çªã) , is the Japanese word for thrust, coming from the verb tsuku (çªã) , meaning to thrust. The second syllable is accented, with Japanese's unvoiced vowels making it pronounced almost like  ski  (but preceded by a t sound).
Thus, it is shortened and simply called tsuki. However, choku-zuki is still used in aikidÅ, and refers to a specific technique with the jÅ (staff). With the student standing in hidari katate-gamae, the weapon is lifted to the right hand, which slides to the bottom end of the weapon.