I'm looking to buy a house and in the 'standard' purchase agreement it
says a "defect" means a condition that would have a significant adverse
effect on the value of the property, that would significantly impair
the health or safety of future occupants of the property, or that if
not repaired, removed, or replaced would significantly shorten or
adversely affect the expected normal life of the premises.

So the inspection comes back with a bunch of small stuff and one major
thing. How do I know what meets the definition of "defect' as quoted
above ? Thank you.

Major item: Deterioration and settlement were noted in the patio.
Repair is needed. The rear elevated porch slab is 15' x 6', and is
broken clean in two. The supporting concrete block structure, the top
few feet of which is visible from the outside and which forms the
basement wall, has deteriorated to the point where much of the mortar
is missing and a few of the blocks have been displaced by half an inch.

Minor items:

Negative slope was noted in the furnace flue pipe. A quarter inch rise
per floor is required.

The furnace flue pipe is in contact with wood in the basement. A 1 inch
clearance is required from combustibles.

The humidifier water panel needs to be replaced.

The furnace burners are short cycling. Service is needed.

Insufficient combustion air supply was noted in the furnace closet.
Proper air supply is needed.

Improper clearance was noted between the furnace flue pipe and
combustibles. Six inch clearance is required.

No overflow pan was noted below the furnace.

The main electrical service wire is less than 10 ft. above the patio.

Visible mold was noted on the upper level bathroom wall and wallpaper.

Visible mold was noted in the half bathroom wall below the sink.

Missing counter flashing was noted at the chimney. Repair is needed.
Existing flashing is not cut into chimney mortar.

Cracking and deterioration were noted in the chimney mortar cap. Repair
is needed.

Improper and unsafe steps were noted at the patio.