Cross section (geometry) of Earth at right. Cross-sections are often used in anatomy to illustrate the inner structure of an organ, as shown at left. A cross-section of a tree trunk, as shown at left, reveals growth rings that can be used to find the age of the tree and the temporal properties of its environment. Cross section (geometry) In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross sections. The boundary of a cross section in
Papal ferula Papal ferula The papal ferula (from Latin "ferula", "rod") is the pastoral staff used in the Catholic Church by the pope. It is a rod with a knob on top surmounted by a cross. It differs from a crosier, the staff carried by other bishops of Latin-rite churches, which is curved or bent at the top in the style of an shepherd's crook. Traditionally, the popes did not use any "ferula", crosier, or pastoral staff as part of the papal liturgy. The use of a staff is not mentioned in descriptions of Papal Masses in the "Ordines Romani" (Roman Ordinals).