The Japanese language is amazing for describing these things for "a word" and "words". 単語 –word, vocabulary, a single-character word 言葉 – word(s), language, speech A WORD 彼はいつも一言多い。- He always says one word too many. 辞書のその文字をご覧。- Look up the word in the dictionary. この単語を省きなさい。- Leave out this word. WORDS 私は言葉に困った。- I was at a loss for words. 最大２００語以内に。- Maximum length: 200 words. 彼の言葉に私は驚いた。- His words surprised me. 言葉が出てこなかった。- Words failed me.

単語＝a word 言葉＝words

単語 words for example 「英単語」　meaning english words. 言葉 has the meaning of 「単語」 but it has another meaning like 「language」