A clear understanding of the difference between fiber pigtail and patch cord

Previously, I only know different in appearance of the fiber pigtail and patch cord.

The fiber optic patch cord = fiber optic connector + fiber optic cable + fiber optic connector

but the fiber optic pigtail = fiber optic connector + fiber optic cable. I think like this is easy to separate between them.

Recently, I have readed a discussion about the difference between fiber pigtail and patch core. There are so many professinal people to discuss it. They give me a clear understanding that:

Patch cords are made from either single or multi-fiber cables (usually rated for indoor use) and connected at each end with fiber cable connectors (either single fiber or multiple-fiber connector). Sometimes patch cords are called jumpers, especially if they are simplex or dulex. The connectors are selected to mate with the interfacing equipment or cable connectors. The important idea is that the cable has a connector at each end. The fiber can be either tight or loose buffered and the cable can be made of various diameters (1.2 mm to 3.0 mm are common). The patch cord may have one type of connector (ST FC, SC, LC, etc) on one end and a different connector on the other as long as all the fibers are connectorized on each cable end - this is a transition jumper. Patch cords are commonly used to connect ports on fiber distribution frames (FDFs). The  new mpo connecter make it  possible to run a singel cable that automatically terminates 12 fibers in one easy plug in.  Compared to common patch cord with ST FC, SC, LC connetor, MPO cable is a truly innovative and amazing group of products that really takes fiber optics into the new millennium.

A pigtail is a cable (like a pach cord or jumper) with only one end terminated with an optical connector. Patch cords are often cut into shorter lengths to make two pigtails. Pigtails are found anywhere, but more commonly in optical assemblages or optical components

Pigtails are installed where they will be protected and spliced,lets say on the inside of the ODF and that's why they are normally not sheathed. They have a coating colour so that you slice them on the corresponding colour on the out coming fiber.
On the other hand patch codes are used between the ODF to the WDM MUX or equipment. If you cut a patch code for use as pigtail then in case of future faulting where you are dealing with multiple pairs it will be difficult. But still if you need to cut the patch code check on its characteristics.

In general, the only major physical differnce b/w patch cord & pigtail is that patch cord is a fixed length piece of cable with dual ended fiber connector type may vary & pigtail is one meter standard OFC core with white white colored jacket. As per standard pigtail can only be used for OFC termination purpose & patch cord is to be used to connect the active component with ODF so that means pigtail can not be used at the place of patch cord.