Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ăgellus, i, m. dim. [ager], a small piece of ground, a little field; Agelli est hic sub urbe paulum quod locitas foras, Ter. Ad. 5, 8, 26: agellus non sane major jugero uno, Varr. R. R. 3, 16: minora dii neglegunt, neque agellos singulorum nec viticulas persequuntur, Cic. N. D. 3, 35.