Bhava sandhi

Bhava Sandhi - The borderline between two house divisions. Planets situated at these points are considered ineffective.

Bhava Sandhi: Junction of two houses
Bhavat bhavam: The house which is as far from the house concerned, as the concerned house is from the ascendant; for example the 4th from the 4th (7th house), or the 9th from the 9th (5th house) ...

See also: House, Benefic, Part, Houses, Degrees