19-letter words containing p, l, o, a
- world day of prayer — the first Friday in Lent, during which Christians belonging to ecumenical communions pray for foreign missions.
- xenotransplantation — xenograft.
- zenithal projection — a type of map projection in which part of the earth's surface is projected onto a plane tangential to it, either at one of the poles (polar zenithal), at the equator (equatorial zenithal), or between (oblique zenithal)