ど

ど

The Japanese word "ど" means "degree" or "how," and is used in questions to inquire about extent, manner, or frequency.

Here, 'ど' functions as an interrogative prefix used with 'れ' to form 'どれ', meaning 'which one'.

どれがあなたの帽子ですか？

Which one is your hat?

In this sentence, 'ど' is part of the compound word '速度', which means 'speed'. It does not independently hold meaning as 'ど' here.

速度(そくど)を上げてください。

Please increase the speed.

'ど' appears as part of the word '角', meaning 'corner'. Similar to the above, its role is integrated into the noun.

次(つぎ)の角(かど)を右(みぎ)に曲(ま)がる。

Turn right at the next corner.