jskeldon,
Some brokers interpret the purchasing and selling of the same security during the day as only 1 daytrade. Thereofe, with those brokers you can trade hundreds of times the same stock all day and this will be considered one daytrade.
With less than 25k, maximum of 3 daytrades in 5 days are allowed before you are declared a pattern daytrader.
With less than 25k margin account with IB, only 3 daytrades in 5 days are allowed and unlimited swingtrades are permitted.
Partial fills are counted as 1 daytrade at IB. But IB seems to count each buy/sell of the same security intraday as 1 daytrade, therefore you can't trade the same stock all day, because that'll generate multiple daytrades.( Buy&sell ORCL - 1 daytrade, Buy&sell ORCL again - 2nd daytrade, maximum 3)
Fohat