• There are rules and restrictions for registering and using trade marks.
• There have been law suits to settle trademark violations.

Apple

• Apple Computers (in USA) was sued by Apple Music (in UK) for trademark violations.
• The judge decided that the name “Apple” was being used in two different industries.
  Little did he know that several decades later iTunes (owned by Apple Computers) would be playing the Beatles music (owned by Apple Music).

Google

• Google is an accidental misspelling of Googol.
• Googol is one followed by 100 zeroes.
  It signifies a very large number.

iPhone

• iPhone is a trade mark owned by Cisco.
• Apple has an agreement with Cisco to use it for its smart phones.

iPad

• iPad is a trade mark owned by Fujitsu.
• Apple has an agreement with Fujitsu to use it for its product.

Name change of products (to avoid Trademark violation)

• NPL (New Programming Language) was renamed by IBM as PL/1 (Programming Language One) due to protest by NPL (National Physical Laboratory)
• FOURTH was renamed as FORTH
• PEARL was renamed as PERL