Definition: The outer layer of tissue that covers the surface of the skull.

Example: The surgeon carefully examined the pericranium before proceeding with the operation.

Definition: A type of plant tissue found in roots, situated between the inner layer of cells and the phloem, which helps in the growth and development of the plant.

Example: The pericycle plays a crucial role in the formation of lateral roots in plants.

Definition: Relating to a specific type of chemical reaction that involves the rearrangement of electrons in a cyclic manner, often occurring in organic chemistry.

Example: The pericyclic reaction is an important concept in understanding molecular transformations.

Definition: The outer layer of tissue found in woody plants, which includes cork and other protective tissues.

Example: The periderm protects the inner layers of the plant from damage and dehydration.

Definition: The outer layer that covers the spore-producing part of certain fungi.

Example: The peridium protects the spores until they are ready to be released.

Definition: A type of rock that is mostly made up of olivine and other minerals, often found deep in the Earth's mantle.

Example: Geologists study peridotite to understand the composition of the Earth's interior.

Definition: Relating to the point in the orbit of the moon or a satellite at which it is closest to the Earth.

Example: The perigean tide occurs when the moon is closest to the Earth, resulting in higher than normal tides.

Definition: The closest point in the orbit of an object around a planet or moon.

Example: The satellite reached its perigee just before it began to ascend again.

Definition: A term used to describe a floral structure that includes the outer parts of a flower, such as petals and sepals, or a geometric concept referring to a full circle or round angle.

Example: The botanist explained that the perigon is essential for understanding the flower's structure.

Definition: This term describes a type of flower structure where the sepals, petals, and stamens are arranged around a cup-like base that contains the ovary.

Example: The rose is an example of a plant with perigynous flowers, where the reproductive parts are positioned around the ovary.