symbl-data/loc/en/symbols-desc/2146.axyml

Lowercase "d" is often used to denote diameter, distance, differential, and one of the varieties of quarks, as well as other mathematical and scientific phenomena. As for formulas and calculations, the italic [U:1D451], bold small [U:1D41D], handwritten [U:1D4B9] from the [BLOCK:mathematical-alphanumeric-symbols] are used.

Double-struck lowercase "d" is rarely seen in scientific works. This unfilled letter with a double outline is commonly used for decorative purposes in texts. Copy and paste it in your nickname or title, on a business card or promotional brochure. This letter combines well with other double-lined symbols from Unicode, such as [U:2147], [U:2148], [U:2149].
	`Lowercase "d" is often used to denote diameter, distance, differential, and one of the varieties of quarks, as well as other mathematical and scientific phenomena. As for formulas and calculations, the italic [U:1D451], bold small [U:1D41D], handwritten [U:1D4B9] from the [BLOCK:mathematical-alphanumeric-symbols] are used.`

	`Double-struck lowercase "d" is rarely seen in scientific works. This unfilled letter with a double outline is commonly used for decorative purposes in texts. Copy and paste it in your nickname or title, on a business card or promotional brochure. This letter combines well with other double-lined symbols from Unicode, such as [U:2147], [U:2148], [U:2149].`