Final answer:
Ringworm of the nail is technically known as tinea unguium or onychomycosis, a fungal infection caused by dermatophytes that leads to yellowing and brittleness of the nails.
Step-by-step explanation:
The technical name for the disease referred to as ringworm of the nail is tinea unguium, often also called onychomycosis. This condition is a type of fungal infection caused by dermatophytes, which are a group of fungi that require keratin (found in skin, hair, and nails) for their growth. Specifically, the fungi responsible for this condition are Trichophyton, Epidermophyton, and Microsporum, which can cause a variety of cutaneous mycoses, including tinea corporis (ringworm), tinea pedis (athlete's foot), and tinea cruris (jock itch). Fungal infections of the nail, like tinea unguium, lead to symptoms such as the nail becoming yellow, brittle, and prone to breaking.