Lexicon

Ailm (Ogham Letter) - from the Ogham script, representing the fir tree. Associated with clarity, purification, resilience, and spiritual progress.

Aos Sí / Daoine Maithe - the "people of the mounds", fairy folk of Celtic mythology, seen as nature spirits or ancestors that influence luck and energy.

Awen - a symbol consisting of three rays or lines representing inspiration, divine creative flow, balance between opposing energies, and harmony.

Book of Kells - an illuminated manuscript created by Celtic monks around 800 CE, widely regarded as a masterpiece of medieval art. It contains the four Gospels of the New Testament, written in Latin and lavishly decorated with intricate knotwork, spirals, and symbolic imagery. Believed to have been produced in a monastery on the Isle of Iona or in Kells, Ireland, the manuscript reflects the fusion of Christian and Celtic artistic traditions. Today, it stands as a symbol of Ireland’s early spiritual and artistic heritage.

Cailleach - the divine hag goddess associated with winter, storms, and the shaping of landscapes; a primordial force of transformation.

Celtic /ˈkɛltɪk/ - pertaining to the Celts, their culture, or their languages, which constitute a branch of the Indo-European family and include Irish, Scottish Gaelic, Welsh, Breton, Manx, Cornish, and many extinct pre-Roman languages such as Gaulish and Galatian.

Celtic Christianity - a distinctive early form of Christian practice that emerged in the British Isles, particularly Ireland and parts of Scotland, from the 4th to the 12th century CE. Blending Christian theology with existing Celtic traditions, it emphasized monastic life, a deep reverence for nature, and localized expressions of faith. Hallmarks include intricately illuminated manuscripts (such as the Book of Kells), unique liturgical practices, and a continued use of native symbols such as knots and spirals. Celtic Christianity fostered a spiritual worldview where creation was seen as a reflection of the divine.

Celtic knot - any of a variety of knots and stylized graphical representations of knots used for decoration, used extensively in the Celtic style of Insular art.

Dara Knot - a complex tree-root‑like knot symbolizing strength, wisdom, endurance, and the power of deep roots.

Druid - a member of the high-ranking class in ancient Celtic cultures, often serving as a religious leader, legal authority, adjudicator, medical professional, or political advisor. While they were reported to have been literate, druids left no written accounts as they are believed to have been prevented by doctrine from recording their knowledge in written form.

Gáe Bulg - the legendary "belly spear" wielded by Cú Chulainn, known for its ritual use and deadly barbs and deeply tied to mythic hero cycles.

Geas (Geis) - a mythological binding vow or taboo that grants power or fate. Central to hero tales in Irish mythology, e.g. Cú Chulainn's geas.

Hallstatt culture - the predominant Western and Central European culture of the late Bronze Age (c. 1200 BCE - 700 BCE) and early Iron Age (c. 700 BCE - 500 BCE), developing out of the Urnfield culture of the 12th century BCE and followed in much of its area by the La Tène culture. It is commonly associated with Proto-Celtic populations.

Insular illumination - the production of illuminated manuscripts in the monasteries of Ireland and Great Britain between the 6th and 9th centuries, as well as in monasteries under their influence on continental Europe. It is characterized by decoration strongly influenced by metalwork, the constant use of interlacing, and the importance assigned to calligraphy.

La Tène culture - (c. 450 BCE - 50 BCE) replaced the earlier Hallstatt culture as the dominant culture of central Europe, especially in terms of art, and later went into decline following the conquest of Gaul by Julius Caesar. Artifacts of the La Tène culture have been discovered in a wide arc covering western and central Europe, spanning from Ireland to Romania.

Lugh - a prominent Celtic deity, also known as Lugus in Britain and the European mainland, or as Llew Llaw Gyffesin Wales, who was principally associated with skill and kingship but often also connected with light or the sun.

Merrow (Muirgeilt) - sea‑dwelling mermaid or merman figures in Irish folklore; creatures of enchantment and maritime mystery.

Ogham /ˈɒɡəm/ - an ancient alphabetical writing system used by the Celts in Ireland and Britain, consisting of straight lines drawn or carved perpendicular to or at an angle to another long straight line.

Oppidum /ˈɒpɪdəm/ - an ancient fortified town built by the Celts in Central Europe between 200 BCE and 100 CE as conflicts arose with Roman culture following increased competition for land and resources.

Triquetra /traɪˈkwɛtrə/ - a triangular figure composed of three interlaced arcs, or (equivalently) three overlapping vesicae piscis lens shapes. Often referred to as the "Trinity Knot", it is used as an ornamental design in architecture, and in medieval manuscript illumination (particularly in the Insular tradition). Its depiction as interlaced is common in Insular ornaments from about the 7th century. In this interpretation, the triquetra represents the topologically simplest possible knot.

Triskelion (Triskele) - a spiral motif consisting of three interlocking spirals, symbolizing cycles of life, mind, body, and spirit, and nature’s continuity.

Urnfield culture - (c. 1300 BCE – 750 BCE) a late Bronze Age culture of Central Europe, often divided into several local cultures within a broader Urnfield tradition. The name comes from the custom of cremating the dead and placing their ashes in urns, which were then buried in fields. Over much of Europe, the Urnfield culture followed the Tumulus culture and was succeeded by the Hallstatt culture. Some linguists and archaeologists have associated this culture with the Proto-Celtic language, or a pre-Celtic language family.

Vesica piscis - a type of lens, a mathematical shape formed by the intersection of two disks with the same radius, intersecting in such a way that the center of each disk lies on the perimeter of the other.

Votive offering - one or multiple objects displayed or deposited, with no intention of recovery or use, in a sacred place for religious purposes. Such offerings are practiced in both modern and ancient societies and are generally given in order to impress or win favor with supernatural forces.