Most folks learn their sun or star sign as an entry point into astrology, largely because it’s what’s most often used in horoscope readings. From there, those who are interested in gaining more cosmic intel might next gain a better understanding of other big-deal components of a natal chart like moon sign, rising sign, different planets, and astrological houses. But even then you may find yourself thinking, I really wish I knew what a trine was. To shed some light, a trine is one of several major astrological aspects, or the ways in which planets interact with each other, and understanding their individual significance can help you level up your understanding of the energetic frequency of the cosmos.

“Aspects in astrology describe the nature of the conversation taking place between planets,” says astrologer and tarot-card reader Maria Sofia Marmanides. “If the planets are the main characters, the signs are the costumes they’re wearing, the houses are the setting or places where the action is happening, then aspects convey how they are relating to each other.”

“Aspects are all about sight—how the planets see each other, or not, at any given moment of time,” astrologer Maria Sofia Marmanides

To be clear, astrological aspects can manifest in a few different ways. If you pull up your birth chart, aspects can show you areas of your life that might have a natural grace or tension. In a synastry chart with someone else, aspects can point to things you may disagree with. Knowing how the planets are relating to each other in the sky can also be helpful for predicting how the day might unfold. “Aspects are all about sight—how the planets see each other, or not, at any given moment of time,” Marmanides says.

There five major astrological aspects (also called the Ptolemaic aspects), and understanding what each means can help you build a foundational understanding for leveling up your understanding of astrology and, eventually, interpreting the stars for yourself. “By starting with the five principle [aspects], and one of the more significant minor aspects, you can add to your astrological vocabulary,” says Marmanides.

Below, your go-to glossary for major astrological aspects

1. Conjunction

Conjunctions (think “conjoined”) are about the merged energies of planets, similar to being born on the cusp of two signs. “Conjunctions suggest a fusing together of two—or more—planets in a single sign, blending together their planetary natures,” says Marmanides. “Depending on the nature of the planets, this can be a wonderfully harmonious joint venture and a powerful partnership—or it can create a sense of one’s toes being stepped on and an overwhelming dominating energy of the planet and sign.”

2. Sextile

Sextiles describe an easy-flowing and helpful nature between two planets in complementary elements. Fire signs form a sextile with air signs, because a breeze can help fan the flames. Water signs form a sextile with Earth signs, because the rain helps the roses to blossom.

“A sextile isn’t the strongest aspect, but it signals that should a planet need support or backup, there’s assistance available,” says Marmanides. “It’s not the most potent aspect if you want to see action. It’s more like a friendly show of support.”

3. Trine

Trines are fortuitous aspects associated with good fortune. They refer to the union of three planets, often in the same element, such as a combination of all fire signs.

“When you want to know if a venture is going to be successful, or if you want to know how easily something will come to fruition, look for a trine,” says Marmanides. “It usually signifies that all systems are a go. Trines mean that events unfold naturally, with little-to-no resistance or effort required.”

4. Square

“Think of squares like a four-way stop sign, and everyone thinks they got to the intersection first,” Marmanides says. Squares are an astrological aspect that’s known for being very action-oriented, but also very hot-headed. As a result, squares suggest conflict and tension are present between two planets that are in the same mode (cardinal, fixed, or mutable), and at 90 degrees from each other.

“It signals that there is an inherent disagreement between the nature of signs, how they prioritize their values,” says Marmanides. “But squares can also propel action and incite movement—and that’s not always a bad thing.”

5. Opposition

Okay, brace yourself, because opposition can be a doozy. It refers to formations in the same mode (cardinal, fixed and mutable) and of the complementary elements (fire and air, earth and water) that can make or break you.

“They have oppositional line of sight to each other, creating a target-like effect,” says Marmanides. “If that manifests as conflict; completion; or eyes-across-the-room, moths-to-a-flame attraction depends on the nature of the planets in those signs. It is important to remember that oppositions usually mean there is a distance between them, but a shared desire to either separate or figure it out.”

Bonus: Inconjunct

Planets that are either one sign away from each other (semi-sextile) or five signs aways from each other (quincunx) can form a sextile. This can go either way, with planets either head-nodding to each other along the room, or facing serious friction.

“An inconjunction of either kind is significant to look at as well, as it usually suggests an awkwardness or adjustment that is necessary,” says Marmanides. “While the semi-sextile might suggest a casual awareness of the other but no overt action or thought towards union, a quincunx can point to deeply averse feelings towards the other as they have contrasting agendas.”