• focu shift,
• focas shift,
• fukus shift,
• focis shift,
• focsu shift,
• foccus shift,
• focuss shift,
• focuse shift,
• focuz shift

The adjective form of "focus shift" is "focused" or "shifting".

The plural form of "focus shift" is "focus shifts".

The singular form of the word "focus shift" is "focus shift". The term remains the same in both singular and plural forms.