What is the difference between עצם and חפץ?

[Okapio]

Thanks!

[Casper_duo]

Usually, treat עצם as "bone" and חפץ as "object".
This is the most common translation for עצם.

Now, an example when עצם is synonym with "object" too.
UFO - עב"מ - עצם בלתי מזוהה
The Hebrew is translated to "unidentified object". The same as English but without the flying part.

[litamina]

Pay attention that if עצם is used in the meaning of bone, the plural form is עצמות; and if it's used in the meaning of object, the plural form is עצמים.

[inbarggg]

I will add that as a speaker, חפץ is an artificial thing you can possess, while עצם is not. For example an astronomical object is עצם, but never חפץ. Likewise I wouldn't call stuff I have on my desk עצמים but חפצים.