In Jain cosmology, "2½ Dweep" (also written as "2.5 Dweep" or "ढाई द्वीप") refers to a specific region within the structure of the universe (Loka). According to Jain scriptures, the universe is divided into several continents (dweeps) and oceans (samudras), arranged concentrically around Mount Meru.

The "2½ Dweep" refers to:

1. Jambudweep
2. Dhatkikhand
3. Half of Pushkar Dweep

These are the first two full continents (Jambudweep and Dhatkikhand) and half of the third continent (Pushkar Dweep) counted together. This designation is significant in Jainism because:

• Area of Human Existence: According to Jain philosophy, only in the regions of these 2½ continents can humans be born, live, and practice religion (including the possibility to attain liberation/moksha).
• Spiritual Importance: The rest of the universe, outside these 2½ dweeps, is considered unsuitable for spiritual practice due to unfavorable conditions.

Summary: In Jain cosmology, "2½ Dweep" refers to Jambudweep, Dhatkikhand, and half of Pushkar Dweep—the primary regions within the universe where human beings can be born and where right religious practice is possible.