Genesis 1:14-16 tells us 𝐰𝐡𝐞𝐧 and 𝐰𝐡𝐲 God created the 𝐬𝐭𝐚𝐫𝐬, the 𝐦𝐨𝐨𝐧, the 𝐬𝐮𝐧. They were for “𝐬𝐢𝐠𝐧𝐬 and 𝐬𝐞𝐚𝐬𝐨𝐧𝐬, and for 𝐝𝐚𝐲𝐬 and 𝐲𝐞𝐚𝐫𝐬;…to give 𝐥𝐢𝐠𝐡𝐭 on the earth…..and for 𝐠𝐨𝐯𝐞𝐫𝐧𝐚𝐧𝐜𝐞 “the greater light to 𝐫𝐮𝐥𝐞 𝐭𝐡𝐞 𝐝𝐚𝐲, and the lesser light to 𝐫𝐮𝐥𝐞 𝐭𝐡𝐞 𝐧𝐢𝐠𝐡𝐭.”
When it comes to the moon specifically, there are 𝐟𝐨𝐮𝐫 𝐩𝐫𝐢𝐧𝐜𝐢𝐩𝐥𝐞 𝐥𝐮𝐧𝐚𝐫 𝐩𝐡𝐚𝐬𝐞𝐬 that we cycle through each month. In the Hebraic calendar, the 𝐍𝐞𝐰 𝐌𝐨𝐨𝐧 marks the start of a 𝐧𝐞𝐰 𝐦𝐨𝐧𝐭𝐡. Additionally, there are certain celebrations, feasts, observances that God ordained would fall on certain 𝐝𝐚𝐲𝐬 of the month. All signs that mark cycles. Hope you can see where I’m going with this.
To see a 𝐜𝐫𝐞𝐬𝐜𝐞𝐧𝐭 𝐦𝐨𝐨𝐧, then, speaks of 𝐓𝐈𝐌𝐈𝐍𝐆. 𝐂𝐲𝐜𝐥𝐞𝐬. 𝐒𝐢𝐠𝐧𝐬. 𝐒𝐞𝐚𝐬𝐨𝐧𝐬. Most likely means the dream is meant to highlight something that has to do with an 𝐚𝐩𝐩𝐨𝐢𝐧𝐭𝐞𝐝 𝐭𝐢𝐦𝐞.
The second thing I would say is that a 𝐜𝐫𝐞𝐬𝐜𝐞𝐧𝐭 𝐦𝐨𝐨𝐧 is sometimes used as a 𝐬𝐲𝐦𝐛𝐨𝐥 by certain groups or religions. 𝐈𝐬𝐥𝐚𝐦, for example, being one of the most popular. 𝐒𝐢𝐧𝐠𝐚𝐩𝐨𝐫𝐞 has a crescent and five stars on their flag.
So depending on what the dream overall communicated, and how the crescent was used in the dream, that’ll give you more context on how to interpret its symbolism.