But on to more serious matters. It's a rather random word today...and the word is "knock"
There are random memories associated with this word from Brazil, where knocking on the physical door to a household is unheard of and "knocking" consists of clapping very loudly from the front gate. It reminds me of trekking around Bela Vista VBS with David Blanchard, trying to convince the Brazilians with David's very limited Portuguese that VBS was a good idea and their kids should come.
Knocking is kind of a cultural thing I guess...so I'll just come at it from how I've always been raised. Knocking indicates presence. It indicates an immediate desire to enter, paralleled by an unspoken respect that whoever is knocking will not force themselves in. It requires an equal desire from the person on the inside of the door, to want to be in the presence of the person outside the door. Entrance (especially to a home) indicates intimacy, a desire for deeper relationship, and a certain level of trust.