Does one tick on WhatsApp mean blocked?
No, when you send a message to any contact first you can see there is a single tick means the message is delivered, then it turns to double tick which means the message is delivered to the user. When you see there is a double blue tick that specifies the message is read by the receiver. It will show you are not blocked. But when you send the message and it will remain in a single tick then this will indicate you have been blocked. But only this indication is not sufficient for drawing any conclusion. Maybe the person’s internet is off due to which you can see only a single tick.