AHDEL gives the following definitions of exhibit:

exhibit noun

 

1. The act or an instance of exhibiting.

2. Something exhibited: studied the dinosaur exhibits at the museum.

3. A public showing; an exhibition: spent the afternoon at the space exhibit.

4. Law Something, such as a document, formally introduced as evidence in court.

Judging from the third definition, exhibit and exhibition are synonyms, overlapping in OP's sense.

AHDEL gives the following definitions of exhibit:

exhibit noun

1. The act or an instance of exhibiting.

2. Something exhibited: studied the dinosaur exhibits at the museum.

3. A public showing; an exhibition: spent the afternoon at the space exhibit.

4. Law Something, such as a document, formally introduced as evidence in court.

Judging from the third definition, exhibit and exhibition are synonyms, overlapping in OP's sense.

The FreeOnline Dictionary does give the following definition of exhibit

exhibit

n.

1. The act or an instance of exhibiting.

2. Something exhibited: studied the dinosaur exhibits at the museum.

3. A public showing; an exhibition: spent the afternoon at the space exhibit.

4. Law Something, such as a document, formally introduced as evidence in court.

Judging from the third definition, exhibit and exhibition are synonyms (apart from some quite specific meanings)

AHDEL gives the following definitions of exhibit:

exhibit noun

1. The act or an instance of exhibiting.

2. Something exhibited: studied the dinosaur exhibits at the museum.

3. A public showing; an exhibition: spent the afternoon at the space exhibit.

4. Law Something, such as a document, formally introduced as evidence in court.

Judging from the third definition, exhibit and exhibition are synonyms, overlapping in OP's sense.