Urinary incontinence comes in many forms.
Stress urinary incontinence is the loss of urine associated with decreased strength of the pelvic floor muscles. This is the loss of urine associated with coughing, laughing, lifting, etc...
Urge urinary incontinence (overactive bladder syndrome) occurs when the bladder contracts and empties without control. This is usually a larger loss of urine. This is also characterized by very frequent urges to urinate and sometimes with the feeling that there has been incomplete emptying of the bladder.
Mixed incontinence is a combination of stress and urge incontinence.
Functional incontinence is loss of urine associated with not being able to get to the toilet. This is primarily a mobility issue (i.e. broken hip).