This is the 1204th most frequent Russian word.
зерно
Grain.
Here, 'зерно' is used to refer to agricultural produce, specifically cereal grains.
На ферме хранится много зерна урожая текущего года.
The farm stores a lot of grain from this year's harvest.
In this context, 'зерно' metaphorically refers to a small but significant piece of truth or value within a statement or idea.
В словах мудреца мы нашли зерно истины.
In the words of the sage, we found a kernel of truth.
Here, 'зерно' is used in the sense of seeds or granular food, which serve as sustenance for animals.