A sailor's knife would be a (folding) marlinspike for the purpose of weaving/braiding/splicing rope.
The meter should be on the AC scale. In Canada and US the reading should be 240 on the outside blade holes and 120 volt from the outside blade holes to the center blade hole. The U shaped pin is the ground. No voltage from it to the center pin.
spiracles
Holes.
Need more info, How long is the blade, do you mean literally the bolt on blade across the bottom or the whole thing (curved section, mounting holes ect.) hopefully this is clear
They are called "black holes".
The holes on your sneakers are called 'eyes'
Holes.
holes
Millipedes breathe through small holes called spiracles. Spiracles function similar to the gills of a fish and never close completely. These holes are found in pairs along the millipedes body.
Cockroaches breathe through the tiny holes called spiracles which are present along the side of their body. Oxygen enters the cockroach through these holes and follows the tiny breathing tubes called tracheae to all of the cockroach's body parts.
I do not know if they have a musical name but they are commonly just called Recorder Holes.
The F holes in a cello are called... <drum roll!> F-holes! They are also called 'sound holes', and acousticians might refer to them as 'ports'.