Nothing, except that 'width' is a more accurate description. I have only ever used width, length and minimum dimension, never thickness. I guess thickness could mean the thickness of the seed coat?

Hi!

I totally agree with Andrew Paul McKenzie Pegman answer. Thickness is not accurate and depend on the viewer.

Thank You sir for your valuable comment.

Dear Akshit

As suggested by Dr. Harouna and Dr. Pegman seed width would be more accurate description but if its a mandate for you to evaluate the seed thickness then vernier calliper might come in handy

Dimensions are important when we need to grading the seeds. In fact, all the seeds have length, width and thickness. The reference to decide about these dimensions is the position of the hilum. In short, there is no spherical seed. Please see the soybean seeds. The length follow the line of the hilum, the width is measured from the hilum to the opposite side of the seed, and the thickness is measured from one cotyledon side to the other. In corn, the thickness is the large dimension in the upper side of the cariopse using the both sides of the only one cotyledone as the reference because it is the location where the perforate metal screen will classify these seeds. The best way to decide is to imbibe the seeds to identify all these places. You could attach an image of the seed in the question above. In the case of small seed, the best is to measure with a digital calliper to be fast. I hope this can help you, Sincerely, Walter

The thickness of seed is the distance between the upper and lower surface of the seed

The length of the grain is the distance between the top and bottom of the seed

The width of seed is the distance between the sides of the seed lying on the flat surface

easily can understand by sundus eg