What is a micro?

[butchndad]

Good morning.

Is there an accepted demarcation of what constitutes a micro?  

Is it 1/4 inch or smaller?  These two Crows are 5/16 inches.  

The other photo is, I think, just a cusp which is 1/8 inch.  Thanks all.

 

 

[Fossildude19]

Technically, I believe this is the answer: 

 

From MeriamWebster.com/dictionary:

 

Personally, I would call anything smaller than 5 mm a "microfossil". 

 

 

[grandpa]

Here's a quantification of microfossil from:

https://en.wikipedia.org/wiki/Micropaleontology

" Microfossils are fossils that are generally between 0.001mm and 1 mm in size,^[1] the study of which requires the use of light or electron microscopy. Fossils which can be studied with the naked eye or low-powered magnification, such as a hand lens, are referred to as macrofossils. "