Deer
noun
The kanji and the word are exactly the same. That means they share meanings as well.
しか
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you to remember: You're staring really closely at this deer, but something looks off. You get closer, slowly, and you realize it's a sheep in a car (しか) shaped like a deer. The sheep car deer suddenly turns toward you rushing forward, legs raised. Ahh, get outta there! (The lesson here is to never get too close to a deer. You never know its true form until it's too late.)
牡鹿と牝鹿の区別がつきません。
I can’t distinguish between male and female deer.