I am wondering about these two bug priority during development testing.
Major has more impact on how users can or cannot use the application than minor.
There is no industry standard what these terms mean. If it is necessary, you need to discuss the meaning with your team/company, as the meaning should relate to which action, turn-around time should be used.
Personally I do not care for priorities in words. Rather prioritize everything against each other. This defect is more important then this one. When prioritized fix them one by one. I suggest you use a zero-defect policy for clasification instead.
Bugs can be classified according to priority. Classifications to use are as follows:
Major Bugs: These bugs share many of the same criteria as show-stopper bugs. However, they are not classified as Show-stopper because they don’t completely halt the workflow or application. Additionally, high priority bugs can usually be avoided by using a workaround.
Bugs that cause a severe reduction in application functionality
Irregular bugs or those that are challenging to reproduce
Bugs related to compliance failure
Minor Bugs: This type of bug does not result in complete system failure or completely halt workflows or programs. However, Minor bugs usually cause significant annoyance or frustration among users and can reduce efficiency or productivity.
App design and UI bugs
Bugs that prevent music, video or audio from being played
Bugs impacting shaders and other graphic design elements
Camera or clipping errors
The definition of these terms is whatever your business decides to agree that they mean.
This is important to agree and communicate, so that when people create a new bug or see a bug, they can immediately tell something about it based solely on that priority field. If there is not common agreement on the definition of these priorities, they become much less useful and more of a waste of time.
As new situations are encountered and the bug policy doesn't seem to give good guidance, discuss it, agree on it, and document that decision by updating the policy.
A very simple example might be something like:
Major bug: Danger to human life; Damage to equipment; Program crash; Requires power cycle to recover; Loss of user data; critical calculation incorrect; etc.
Minor bug: Cosmetic issue (wrong color/incorrect font); A workaround exists; Documentation problem; Degraded user experience (but still functioning) to some limit; etc.
However, when you get a lot of bugs, and have few priorities (in this example 2), eventually you will encounter a situation where you have a large set and at that point you really can't distinguish within the bugs within each group. Ranking bugs relative to each other as Niels mentions in his answer can have other benefits - like actually sequencing the order that they are addressed and seeing at a glance where it fits in the (possibly big pile of) work.