Polyuria or PU means excess drinking.
Polydypsia or PD means excess thirst.
Both can occur as a result of urinary tract problems but also for a variety of reasons unrelated to kidney function. Technically, PD means consuming more than 100 ml of water per kilogram of body weight daily. Remember, this includes fluid in food as well as fresh water. PU means passing more than 50 ml of urine per kilogram of body weight daily.
Incontinent means unable to control the discharge of urine. A dog may constantly leak urine or only release urine when lying down or excited. There are different forms of incontinence with different causes.
Frequency refers to how often a pet urinates. PU/PD may or may not be associated with increased frequency or incontinence.