Alan Leo book question

[VieuxDonjon]

I am reading "How to Judge a Nativity" and in the house chapters, especially the 7th house chapter that brings this question up I keep reading something about one planet "applying" to anothing, for instance:

"When the moon is applying to or forms any aspect to Uranus, the native should guard against a sudden or hasty marriage..."

What does "apply" mean in this sense?

Thanks,
Michael

[VieuxDonjon]

One more question through the reading. What does "apply" mean in this sentence, again from Leo's How to Judge a Nativity:

"in the male horoscope the wife is always described by the planet to which the moon first applies...", page 194 of the 1973 reprint.

Thanks,
Michael

[Yennefer]

Applying aspect is an aspect than has not been perfected/exact yet. Like Moon at 3.23 Virgo is applying square to Uranus at 15.36 Sagittarius, Moon still has some twelve degrees to travel until it reaches exact square.

Now imagine that in a male chart, there is is Moon at 14.34 Aries and let´s say Mercury at 20.41 Gemini, Neptune at 21.23 Libra and Venus at 15.00 Aries.
Moon will reach conjunctuion with Venus first.

[dr. farr]

As Yennefer correctly explained, its when a planet is moving toward the degree which makes that aspect perfect or exact; the "moving toward" is the key concept, moving toward making the aspect exact.